Maxum II. PD PA AP Explosion Protection Safety Standards. General Information for the User 1. Safety Systems - Purging 2. Safety Systems - Oven 3

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1 General Information for the User 1 Safety Systems - Purging 2 Maxum II PD PA AP Explosion Protection Safety Standards Safety Systems - Oven 3 Valves, Detectors, and External Systems 4 Safe Operation 5 Manual August 2017 A5E Rev 8

2 Legal information Warning notice system This manual contains notices you have to observe in order to ensure your personal safety, as well as to prevent damage to property. The notices referring to your personal safety are highlighted in the manual by a safety alert symbol, notices referring only to property damage have no safety alert symbol. These notices shown below are graded according to the degree of danger. DANGER indicates that death or severe personal injury will result if proper precautions are not taken. WARNING indicates that death or severe personal injury may result if proper precautions are not taken. CAUTION indicates that minor personal injury can result if proper precautions are not taken. NOTICE indicates that property damage can result if proper precautions are not taken. If more than one degree of danger is present, the warning notice representing the highest degree of danger will be used. A notice warning of injury to persons with a safety alert symbol may also include a warning relating to property damage. Qualified Personnel The product/system described in this documentation may be operated only by personnel qualified for the specific task in accordance with the relevant documentation, in particular its warning notices and safety instructions. Qualified personnel are those who, based on their training and experience, are capable of identifying risks and avoiding potential hazards when working with these products/systems. Proper use of Siemens products Note the following: Trademarks WARNING Siemens products may only be used for the applications described in the catalog and in the relevant technical documentation. If products and components from other manufacturers are used, these must be recommended or approved by Siemens. Proper transport, storage, installation, assembly, commissioning, operation and maintenance are required to ensure that the products operate safely and without any problems. The permissible ambient conditions must be complied with. The information in the relevant documentation must be observed. All names identified by are registered trademarks of Siemens AG. The remaining trademarks in this publication may be trademarks whose use by third parties for their own purposes could violate the rights of the owner. Disclaimer of Liability We have reviewed the contents of this publication to ensure consistency with the hardware and software described. Since variance cannot be precluded entirely, we cannot guarantee full consistency. However, the information in this publication is reviewed regularly and any necessary corrections are included in subsequent editions. Siemens AG Division Process Industries and Drives Postfach NÜRNBERG GERMANY Document order number: A5E P 09/2017 Subject to change Copyright Siemens AG All rights reserved

3 Table of contents 1 General Information for the User Contacts Approved Use Qualified Personnel Applicable Standards and Regulations Safety Protection Principles Intrinsically Safe Devices Safety Systems - Purging Purging Overview Electronics Purging System (without Automatic Purge Unit) Overview Instrument Air Inlet and Regulator Fast Purge Switch Purge Control Module SYSCON or CIM and Purge Alarm Light Pressure Sensor and Atmospheric Pressure Reference Fast Purge Pressure Relief Valve Electronics Purging System (with Automatic Purge Unit) Overview Purge Air Inlet and Regulator Proportional Valve Automatic Purge Control Unit Maintenance Switch Exhaust Diffuser Signal Disconnect Relay Maintenance Considerations for Purged Systems Safety Systems - Oven General Oven Information Isothermal Air Bath Oven Heater System (Single and Split) Purging Temperature Control Programmed Temperature Air Bath Oven Heater System (Split) Isothermal Airless Oven Heater System (Split) Maintenance Considerations for Air Bath and Airless Ovens Modular Oven Heater System Maintenance Considerations Modular Ovens...43 Manual, August 2017, A5E Rev 8 3

4 Table of contents 4 Valves, Detectors, and External Systems Heated Siemens Liquid Injection Valve (SLIV) SLIV Functional Description SLIV Maintenance Considerations Detectors Detector Functional Descriptions Detector Maintenance Considerations Air Treater Air Treater Functional Description Air Treater Maintenance Considerations Methanator Methanator Functional Description Methanator Maintenance Considerations Safe Operation Maintenance Panel Functional Description Maintenance Considerations for Maintenance Panel Color Touchscreen Display Functional Description Maintenance Considerations for Control Interface Module Display Steps for Safe Startup of Maxum II Overview Procedure...60 Glossary...63 Figures Figure 1-1 Figure 1-2 Figure 2-1 Figure 2-2 Figure 2-3 Figure 2-4 Figure 2-5 Figure 2-6 Figure 2-7 Figure 2-8 Figure 2-9 Figure 2-10 Figure 2-11 Figure 2-12 Reference of Hardware (MAA) to Applicable Sections of this Manual...8 Reference of Hardware (MMO) to Applicable Sections of this Manual...8 Electronics Pressurization System (Type py) for Airbath/Airless Oven Model (New pressure relief valve configuration)...18 Electronics Pressurization System (Type py) for Airbath/Airless Oven Model (Old pressure relief valve configuration)...19 Electronics Pressurization System (Type py) for Modular Oven Model...19 Instrument Air Inlet and Pressure Regulator...20 Fast Purge Switch (Shown in the Off Position)...22 Purge Control Module...23 Purge Alarm Indicator Lamp...23 Pressure Sensor on PECM Board...24 Atmospheric Pressure Reference for Purge...24 Pressure Relief Valve for PY Purge...25 APU System Component Layout (Modular Oven model)...26 Purge Air Inlet and Pressure Regulator Manual, August 2017, A5E Rev 8

5 Table of contents Figure 2-13 Figure 2-14 Figure 2-15 Figure 2-16 Figure 2-17 Figure 2-18 Figure 2-19 Figure 3-1 Figure 3-2 Figure 3-3 Figure 3-4 Figure 3-5 Figure 3-6 Figure 3-7 Figure 3-8 Figure 4-1 Figure 4-2 Figure 4-3 Figure 4-4 Figure 4-5 Figure 4-6 Figure 4-7 Figure 4-8 Figure 4-9 Figure 4-10 Figure 5-1 Figure 5-2 Proportional Valve...28 Automatic Purge Control Unit (APU) shown in Airless/Airbath model...29 Location and Close-Up of Maintenance Switch (MAA, Set for Normal Operation)...30 MMO APU Maintenance Switch...30 Covered Purge Exhaust Diffuser...31 Signal Disconnect Relays...32 Purge Disable Jumper on PECM or PECM-DC (Shown with Alarm Disabled)...33 Pressure Switch for Purge Control Module...36 Timing Coil for Pressure Switch...37 Programmed Temperature Air Bath Oven (with Deflector)...38 Airless Oven...39 Location of Temperature Probes and Heaters on Airless Oven...40 Heat Retainer Plug for Airless Oven...40 Typical Modular Oven Configuration...42 Heater and RTD Tubes for the Modular Oven...43 Siemens Liquid Injection Valve...45 Siemens Liquid Injection Valve (Installed)...46 Heater for Siemens Liquid Injection Valve...46 Explosion Proof/Flameproof Thermal Conductivity Detector...49 Thermal Conductivity Detector Beads on Modular Oven Application Module (Intrinsically Safe TCD)...50 Flame Ionization Detector (without Insulation and Cover)...51 Flame Photometric Detector (without Insulation and Cover)...51 Air Treater...52 Purged Methanator...54 Explosion Proof Methanator...55 Maintenance Panels - Color Touchscreen (left) and legacy HMI (right)...57 Color Touchscreen Display...59 Manual, August 2017, A5E Rev 8 5

6 Table of contents 6 Manual, August 2017, A5E Rev 8

7 General Information for the User 1 The Maxum II Process Gas Chromatograph employs several design and construction features which conform to various international safety standards. These standards are to ensure that the Maxum II and related products can be safely installed and operated in hazardous areas. Each individual detail and component of these safety systems is important to help ensure that the chromatograph does not ignite flammable vapors and gases which may be present in the environment surrounding the analyzer. Therefore, it is important that any personnel that come in contact with the analyzer be familiar with the operation of the safety systems so that they are less likely to compromise safe operation while performing routine maintenance, operation, or other tasks. This manual provides an overview and general description of the primary safety systems used in the Maxum II. Also, this manual provides guidelines and procedures that should be followed to avoid damage to the safety systems. Note, it is not possible in this manual to describe every possible operation or maintenance situation. At all times, maintenance and operation should be performed only by properly trained and experienced personnel who are familiar with explosion prevention designs in electrical apparatus. In addition, Maxum II maintenance and operation procedures should be supervised and approved by plant personnel who are knowledgeable in local safety regulations and practices. Also, this manual does not provide specific instructions for installation, operation, or maintenance. Those topics are covered in other manuals. The exact configuration of any Maxum II Process Gas Chromatograph depends on the application. Therefore, the information in this manual is general in nature and may not apply to specific installations. This manual includes figures and illustrations that are not formal design drawings to explain maintenance issues and device function. Note however, that formal design drawings of all safety systems are an integral part of the safety certifications for the Maxum II. This manual describes the safety systems in several sections that relate to the various portions of the hardware. In addition, a special section is provided to describe normal, safe instrument startup. Figure 1-1 for the Maxum Airless/Airbath configuration (MAA), and Figure 1-2 for the Maxum Modular Oven configuration (MMO), identify the layout of the safety systems of the Maxum II and associate various portions of the hardware to the relevant sections in this document. Note that some hardware, such as the Automatic Purge Unit (APU), may be optional depending on configuration. Manual, August 2017, A5E Rev 8 7

8 General Information for the User Automatic Purge Unit (APU) or Pressure Relief Valve (Inside Enclosure) Sections 2.2, 2.3 Exhaust Diffuser Sections 2.2, 2.3 Electronics Enclosure (Purged) Sections 2.2, 2.3 Signal Disconnect Relay for APU Section 2.3 Touch Screen or Maintenance Panel Section 5.1 Detector Enclosure (Including Detectors and Methanator) Sections 4.2, 4.4, 4.5 Proportinal Valve for APU (Section 2.3) or Purge Control Module (Section 2.2) Purge Air Inlet & Regulator Sections 2.2, 2.3 Oven Enclosure (Air Bath Oven Shown) Sections 3.1 to 3.5 Heated Valve Section 4.1 Air Treater Section 4.3 Figure 1-1 Reference of Hardware (MAA) to Applicable Sections of this Manual Automatic Purge Unit (APU) or Pressure Relief Valve (Inside Enclosure) Sections 2.2, 2.3 Signal Disconnect Relay for APU Section 2.3 Exhaust Diffuser Section 2.2, 2.3 MAXUM edition II Electronics Enclosure (Purged) Sections 2.2, 2.3 Purge Control Module (Section 2.2) Proportinal Valve for APU (Section 2.3) CIM Display Section 5.1 Oven Enclosure for Modular Oven Sections 3.6 to 3.7 Intrinsically Safe Detector Personality Module (DPM) Section 4.2 Figure 1-2 Reference of Hardware (MMO) to Applicable Sections of this Manual 8 Manual, August 2017, A5E Rev 8

9 General Information for the User See also Fast Purge Pressure Relief Valve (Page 25) Copyright Notice Contents copyright 2017 by Siemens AG. All rights reserved. This publication is for information only. The contents are subject to change without notice and should not be construed as a commitment, representation, warranty, or guarantee of any method, product, or device by Siemens. Reproduction or translation of any part of this publication beyond that permitted by Sections 107 and 109 of the United States Copyright Act without the written consent of the copyright owner is unlawful. Trademarks All names identified by are registered trademarks of Siemens AG. The remaining trademarks in this publication may be trademarks whose use by third parties for their own purposes could violate the rights of the owner. Manual, August 2017, A5E Rev 8 9

10 General Information for the User 1.1 Contacts 1.1 Contacts Register at the Siemens Industry Online Support (SIOS) website: International Siemens AG I IA SC PA PM Process Analytics Oestliche Rheinbrueckenstrasse Karlsruhe Germany Tel: Fax: Web site: Training Tel: pia-training.i-ia@siemens.com Spares Contact your local Siemens sales representative Support Tel: USA Siemens Industry, Inc West Sam Houston Parkway North Suite 500 Houston, TX USA Tel: Fax: saasales.industry@siemens.com Web site: Training Tel: (USA) saatraining.industry@siemens.com Spares Tel: (USA) Tel: (International) PAspareparts.industry@siemens.com Support Tel: (USA) Tel: (International) GCsupport.industry@siemens.com Singapore Siemens Pte. Limited I IA SC Process Analytics 9 Woodlands Terrace Singapore Online Support Request Web site: Tel: Fax: splanalytics.sg@siemens.com Web Site: 10 Manual, August 2017, A5E Rev 8

11 General Information for the User 1.3 Qualified Personnel 1.2 Approved Use The Maxum edition II gas chromatograph is primarily used in all branches of the fine chemicals, refining, and hydrocarbon processing industries. It performs chemical composition analysis of gases and liquids that are present in all phases of production. The Maxum II is built for installation in harsh environments either directly or nearby in at-line process measurement laboratories. The application flexibility of the Maxum II allows it to analyze a wide variety of samples including feedstock, partially processed streams, final products, and process byproducts including wastes and environmental hazards. The Maxum II product is intended to be used only in conjunction with other devices and components which have been recommended and approved by Siemens. Appropriate safety standards were used in the development, manufacture, testing, and documentation of the Maxum II. Under normal operation, this product is safe for use providing that all safety and handling guidelines are observed with respect to configuration, assembly, approved use, and maintenance. This device has been designed such that safe isolation is guaranteed between high and low voltage circuits. Low voltages which are connected must also be generated using safe isolation. If any part of the Maxum II is opened, certain parts of the device are accessible which may carry dangerous voltages. Therefore, only suitably qualified personnel may work on this device as indicated in the next section which is titled "Qualified Personnel". 1.3 Qualified Personnel Only suitably qualified personnel may operate or perform maintenance on the Maxum II. For the purposes of safety, qualified personnel are defined as follows: Those who have been appropriately trained for the tasks which they are performing (for example, commissioning, maintenance, or operation). Those who have been appropriately trained in the operation of automation technology equipment and are sufficiently acquainted with Maxum II documentation. Those who are familiar with the safety concepts of automation technology and are sufficiently acquainted with Maxum II documentation. Those who are authorized to energize, ground, and tag circuits and devices in accordance with established safety practices may perform the tasks for which they are trained. WARNING Operation or Maintenance of the Maxum II by unqualified personnel or failure to observe the warnings in this manual or on the device may lead to severe personal injury and/or extensive property damage. Manual, August 2017, A5E Rev 8 11

12 General Information for the User 1.4 Applicable Standards and Regulations 1.4 Applicable Standards and Regulations When proper precautions are observed, the Maxum II Process Gas Chromatograph is designed for safe use in locations rated as ATEX Zone 1 or Zone 2, or Class I Division 1 or Division 2. Local safety and electrical codes must be observed for installation, operation, and maintenance of the Maxum II. No work should be done on an analyzer without the consent and approval of all applicable safety authorities. This may include obtaining necessary work permits (e.g. "hot work" permit). Any changes may affect safety certifications. An analyzer should never be installed or operated in a location that is more hazardous than that for which the analyzer was designed. This includes the temperature class, which is also called the T Rating. For reference purposes, table 1-1 lists the applicable Maxum II temperature limits for areas rated T1 to T4. Refer to section 3.1 (General Oven Information) for more information regarding temperature constraints for the Maxum II. Temperature Classification Surface Temperature Limit C Agency - Approved, Safe Operating Temperature Limit* T T T T *Note the maximum operating temperature limit that is approved by the certifying agencies is lower than the specified ignition temperature limit of the area classifications. Note: The Modular Oven Configuration always operates below 100 C, and can thus be installed in all T-rated locations down to T4. C The Maxum II Process Gas Chromatograph conforms to ATEX directive 94/9/EC for safe use in ATEX Zone 1 or Zone 2 environments. The ATEX certificate for the Airbath/Airless Oven Configuration is ISSeP10ATEX033X and comes with the following conditions for safe use: The material will be equipped with cable entries of a suitable type ATEX / Ex e. The display may resist impact up to 2 Joules. It is the manufacturer's responsibility to choose the correct value of resistance for the determination of the temperature class. The ATEX certificate for the Modular Oven Configuration is Sira 12ATEX1260X and comes with the following conditions for safe use: The Maxum II Modular Oven Gas Chromatograph shall be fitted with cable glands or conduit entries having an IP54 minimum rating. The Maxum II Modular Oven Gas Chromatograph shall contain shunt zener diode interfaces that are connected to the external earth stud. This shall be connected to a suitable intrinsically safe earth in accordance with EN :2007 clause Manual, August 2017, A5E Rev 8

13 General Information for the User 1.5 Safety Protection Principles Typical ATEX Certification Markings for Maxum II with Modular Oven Typical ATEX Certification Markings for Maxum II with Airless/Airbath Oven 1.5 Safety Protection Principles Several different types of protection principles are used within the Maxum II and its components. These include intrinsically safe circuits, pressurization, explosion-proof enclosures, etc. The protection principles used depend on such factors as the type of device, the certifying organization that is applicable for the site, and the type of environment. Table 1-2 details some of the protection principles used in the Maxum II along with the hardware that uses those protection principles. Type of Protection Principle Applicable Devices Applicable Certificate Intrinsic Safety Programmed Temperature Oven Heater. Color Touchscreen Intrinsically Safe TCD DPM Type X Pressurization (Px) Electronics Enclosure (EC) Liquid Injection Valve Heater* Purged Methanator* Air Bath Oven Heater Modular Oven Heater* CSA & ATEX ATEX for the EC, Methanator, and LIV Heater, and Modular Oven Heater ATEX and CSA for Air Bath Oven Heater Manual, August 2017, A5E Rev 8 13

14 General Information for the User 1.6 Intrinsically Safe Devices Type of Protection Principle Applicable Devices Applicable Certificate Type Y Pressurization (Py) Electronics Enclosure (EC) Liquid Injection Valve Heater* Purged Methanator* Modular Oven Heater* Flameproof Housing Flame Ionization Detector Flame Photometric Detector Thermal Conductivity Detector (with Explosion-Proof/ Flameproof Housing) Airless Oven Heater Air Treater Methanator Explosion Proof Housing Flame Ionization Detector Flame Photometric Detector Thermal Conductivity Detector (with Explosion-Proof/ Flameproof Housing) Airless Oven Heater Air Treater Methanator CSA and ATEX ATEX * Note: Although the Purged Methanator is located in the Detector Enclosure and the Liquid Injection Valve Heater is located in the Maxum oven, they are connected in such a way that the interior of these components are effectively part of the Electronics Enclosure (EC). As a result, they are part of the same purging system as the EC. This is also true for the heaters for the Modular Oven, which are connected in such a way that they are effectively part of the EC. Table. 1-2: Safety Protection Methods in the Maxum II CSA 1.6 Intrinsically Safe Devices Intrinsic safety is a method of protection where a circuit is designed such that it will not create a spark or other condition capable of causing ignition of flammable vapors or gases, even under fault conditions. Various circuits in the Maxum analyzer utilize this form of protection, including the IS TCD and the connections to the CIM touch screen display. Intrinsic safety protection for circuits and devices within the Maxum II enclosure is designed to conform to IEC EN This is the standard that is applicable to factory installed electrical components and also for circuits that are additionally protected by other methods, such as a purged Maxum enclosure. Because internal Maxum II connections are factory installed wiring, certain labeling techniques that are commonly seen with intrinsically safe circuits are not applicable. Notably blue connectors and wiring that the user may be familiar with are not used. 14 Manual, August 2017, A5E Rev 8

15 General Information for the User 1.6 Intrinsically Safe Devices CAUTION Failure to adhere to the instructions and requirements below could violate the safety protections of the analyzer. Maintenance Considerations for Intrinsically Safe Devices: Maintenance for intrinsically safe devices, such as the IS-TCD, is limited to replacement. Repair or service on-site are not permitted. Intrinsically safe devices in the Maxum II that are equipped with a cover must have the cover attached during use. Leaving the cover off can violate requirements pertaining to mandatory separation from non-is wiring. Intrinsically safe devices in the Maxum II must be operated with all factory installed mounting and grounding hardware secured. IS circuitry within the Maxum requires two redundant chassis grounds. There are two separate grounding connections from the CIM- Base and the IS-TCD to the chassis. Note that redundant grounds from the same device may not be stacked on the same termination point, but grounds from different devices (such as CIM and IS-TCD), may share a termination point. Care must be taken to prevent other wiring from contacting the IS circuitry. This means that other all wiring that is secured must remain secured. If it becomes necessary to unsecure wiring for maintenance, then the wiring must be secured again before placing the equipment back in service. External wiring includes serial cabling, Ethernet cabling, external IO wiring, external power, and any other wiring that enters the Maxum enclosure from outside. For the installation of any external wiring, the wiring must be secured in a minimum of two locations, within 50mm of its termination point and also within 100mm of its termination point. Additionally, secure along its length as needed to prevent it possibly coming within 50mm of any IS circuitry. Any wiring that is not sufficiently secured per the above requirement must have sufficient insulation thickness to add up to at least 1mm of solid insulation, 2mm of encapsulation, or remain on the opposite side of a suitable physical barrier from any IS circuit. The Maxum chassis is required to be earth grounded at the location where it is installed using ground screws connected externally as described in the Maxum Installation Manual ( ). The earth ground used must be as close to the Maxum as possible. Power system ground, from mains power that is brought to the Maxum, is required to be grounded to the cabinet as part of required installation practices for basic safety. Manual, August 2017, A5E Rev 8 15

16 General Information for the User 1.6 Intrinsically Safe Devices 16 Manual, August 2017, A5E Rev 8

17 Safety Systems - Purging Purging Overview For safety purposes, Maxum enclosures that are installed in hazardous locations where flammable vapors or gases may exist must be purged. Purging refers to the process of supplying the interior of the enclosure with protective gas in order to increase the pressure within the enclosure above that of the ambient outside air. This increased pressure creates flow out of the enclosure and prevents flammable vapors or gases from entering the enclosure. It also removes any flammable vapors or gases that may exist within the enclosure. The primary electronic devices of the Maxum II analyzer are housed inside the electronics enclosure (see Figures 1-1 and 1-2). All electronics in the Maxum II are designed to meet North American Division 2 and European Zone 2 safety requirements. This means that these electronics will not cause combustion of flammable vapors or gases under normal conditions. However, safety codes also require that equipment be designed to accommodate abnormal conditions as well as normal conditions. The concern is that electronics inside an enclosure might fail, causing a hot spot, a spark, or some other possible source of ignition. To mitigate this risk, when operating in locations where flammable vapors or gases are present, the enclosure is normally closed and supplied with a flow of clean instrument air. The air ensures that the interior of the enclosure is maintained at a positive pressure relative to the outside and that air always flows out of, rather than into, the electronics enclosure. This "purging" makes sure any flammable vapors or gases located outside the enclosure cannot migrate to the interior of the enclosure where they might contact a possible source of ignition. The type of purging within the Maxum II depends on location-specific requirements. The certification of the analyzer (and hence the applicable purging method) can be identified from the labeling on the analyzer. See Section 1.7 (Applicable Standards and Regulations) of this document for more information. There are two purging methods available in the Maxum II. 1. Purging without Automatic Purge Unit: This is the standard purging method for the Maxum. In this purging method, constant purging pressure is applied. Circuitry on the Power Entry Control Module (PECM or PECM-DC, depending on configuration) of the Maxum II is used to verify positive purging pressure. This circuitry compares interior pressure to exterior pressure to determine whether the proper pressure difference exists. An alarm is generated when purge pressure is lost. 2. Purging with Automatic Purge Unit control: This optional method of purging utilizes a device, called an Automatic Purge Unit (APU), to control the purging system. The APU disconnects electrical power to the Maxum if purge is lost. Manual, August 2017, A5E Rev 8 17

18 Safety Systems - Purging 2.2 Electronics Purging System (without Automatic Purge Unit) 2.2 Electronics Purging System (without Automatic Purge Unit) Overview The standard purging system of the Maxum II is controlled by the Power Entry Control Module (PECM) and the processor board (either SYSCON or CIM, depending on the Maxum II configuration). In the standard purging configuration, an alarm is generated whenever purging pressure is lost. This is referred to as purging with Type Y pressurization (py). An illustration of the typical py system of the Maxum II is shown in the following figures. Pressure Relief Valve System Controller (SYSCON) Air Regulator Instrument Air Input - Clean and Dry Electronics Enclosure Purge Signal Cable PECM to SYSCON Purge Purge Warning Light Power Entry Control Module (PECM) Pressure Sensor Purge Control Module (PCM) Fast Purge Switch Detector Compartment Legend Fast Purge Air Flow Normal Purge Air Flow Inside Electronics Enclosure Figure 2-1 Electronics Pressurization System (Type py) for Airbath/Airless Oven Model (New pressure relief valve configuration) 18 Manual, August 2017, A5E Rev 8

19 Safety Systems - Purging 2.2 Electronics Purging System (without Automatic Purge Unit) System Controller (SYSCON) Air Regulator Instrument Air Input - Clean and Dry Electronics Enclosure Purge Signal Cable PECM to SYSCON Purge Purge Warning Light Power Entry Control Module (PECM) Pressure Sensor Purge Control Module (PCM) Fast Purge Switch Detector Compartment Pressure Relief Valve Legend Fast Purge Air Flow Normal Purge Air Flow Inside Electronics Enclosure Figure 2-2 Electronics Pressurization System (Type py) for Airbath/Airless Oven Model (Old pressure relief valve configuration) Pressure Relief Valve Electronics Enclosure Purge Warning Light (outside door) Purge Fast Purge Switch Purge Control Module (PCM) Air Regulator Instrument Air Input - Clean and Dry CIM-Board (inside door) Purge Signal Cable PECM-DC to CIM-Board PECM-DC (back wall of enclosure) Pressure Sensor Pressure Reference Modular Oven Compartment Legend Fast Purge Air Flow Normal Purge Air Flow Inside Electronics Enclosure Figure 2-3 Electronics Pressurization System (Type py) for Modular Oven Model Manual, August 2017, A5E Rev 8 19

20 Safety Systems - Purging 2.2 Electronics Purging System (without Automatic Purge Unit) In this configuration air enters the enclosure through one of two possible paths. A pressure sensor on the PECM determines whether the pressure inside the enclosure is higher than the pressure outside the enclosure. If purge pressure is lost, then the PECM sends this status to the System Controller (SYSCON) or Control Interface Module (CIM), depending on which processor is used. The SYSCON or CIM generates an alarm message and turns on the Purge warning light on the front door of the Maxum II analyzer. When purge is operating properly, excess pressure is released through the pressure relief valve. Note that PECM in the above descriptions may refer to the PECM or PECM DC, depending on configuration of the Maxum II. The Type Y pressurization purging system consists of the components described in the following sections Instrument Air Inlet and Regulator This is a pressure regulator with air input that is connected to an instrument air source. The regulator is necessary to prevent excess input air pressure. Depending on the configuration of the Maxum II, the regulator may be labeled as either "Purge" or "Isothermal Oven Air" (refer to the section of this manual regarding Isothermal Ovens for more information). The purge air is connected to the purged electronics enclosure through two possible paths, the "normal" path and the "fast purge" path. These flow paths are shown in figures 2-1 and 2-2 and are described in the following section titled "Fast Purge Switch". All instrument air must be clean (free of particulates and flammable vapors and gases) and dry. Figure 2-4 Instrument Air Inlet and Pressure Regulator 20 Manual, August 2017, A5E Rev 8

21 Safety Systems - Purging 2.2 Electronics Purging System (without Automatic Purge Unit) Fast Purge Switch The fast purge control switch, which is shown in the following figure, is located inside the detector enclosure (middle door) or near the purge air regulator as shown in the figure below. This switch is operated by the user and is used to re-purge the electronics enclosure for a period of 8 minutes after the sealed enclosure has been opened and then re-sealed. The fast purge function moves a large volume of air through the sealed analyzer within the 8 minutes. This is to ensure that positive purge pressure is reached and to allow any possible flammable vapors or gases to be removed from the enclosure. After the 8 minute fast purge time, the switch should be turned off (to the right) so that normal purge air flow can resume. The fast purge switch is connected to the Purge Control Module manifold (described below) to allow air to flow directly into the electronics enclosure. When air is flowing through the fast purge switch, the higher flow should be audible. One of two new labels, one for each hazard zone, is now applied to the cabinet around the fast purge switch. These are indicated in the figure below. Manual, August 2017, A5E Rev 8 21

22 Safety Systems - Purging 2.2 Electronics Purging System (without Automatic Purge Unit) Modular Oven Airbath/Airless Oven Modular Oven fast-purge switch label for Div 2 Modular Oven fast-purge switch label for Div 1 / Zone 1 Figure 2-5 Fast Purge Switch (Shown in the Off Position) 22 Manual, August 2017, A5E Rev 8

23 Safety Systems - Purging 2.2 Electronics Purging System (without Automatic Purge Unit) Purge Control Module This is a manifold located on the right side wall of the electronics enclosure. It is located behind the air circulating fan. There are two openings in the PCM manifold through which the electronics enclosure is purged. The first is the "fast purge" opening which allows a large volume of air to be passed through the enclosure quickly. The second is a smaller opening that is equipped with a restricting orifice that limits the amount of air that flows into the enclosure to a level that maintains positive pressure without wasting air. This second opening is for the "normal" purge flow. Normal Purge Air Inlet (with orifice) Fast Purge Air Inlet (threaded hole) Maxum II Airless/Airbath Maxum II Modular Oven Figure 2-6 Purge Control Module SYSCON or CIM and Purge Alarm Light When the PECM or PECM-DC detects insufficient purge pressure inside the enclosure, a signal is sent to the central processor board for the analyzer (either SYSCON or CIM, depending on configuration). The SYSCON or CIM then generates an alarm and flashes the purge alarm LED on the front door of the Maxum II analyzer electronics enclosure. The purge alarm LED flashes red when an alarm is present. New Touchscreen Display Old HMI Display Figure 2-7 Purge Alarm Indicator Lamp Manual, August 2017, A5E Rev 8 23

24 Safety Systems - Purging 2.2 Electronics Purging System (without Automatic Purge Unit) Pressure Sensor and Atmospheric Pressure Reference The task of detecting whether purge is operating properly is performed by the Power Entry Control Module (PECM). PECM may refer to either the PECM or PECM-DC, depending on the Maxum II configuration. Located on this module is a pressure sensor (Figure 2-7) that detects the pressure inside the enclosure and compares it to the pressure outside the enclosure. If the pressure difference is not adequate (at least 1.0 inches H 2 O or 0.25 kpa) then the PECM sends a signal to the control processor board (either SYSCON or CIM, depending on the device configuration) so that an alarm can be generated. The pressure sensor detects outside pressure using a small reference tube through the wall of the analyzer (see Figure 2-8). This tube is used only for reference and air does not flow through it. Modular Oven (On Bottom Right of PECM-DC) Airbath/Airless Oven (Not Visible When PECM is Installed) Figure 2-8 Pressure Sensor on PECM Board Modular Oven (Inside Side Panel) Airbath/Airless Oven (On Back) Figure 2-9 Atmospheric Pressure Reference for Purge 24 Manual, August 2017, A5E Rev 8

25 Safety Systems - Purging 2.2 Electronics Purging System (without Automatic Purge Unit) Fast Purge Pressure Relief Valve The pressure relief valve, which is shown in the following figure, is located either inside the detector enclosure (middle door or a Maxum II with Airbath/Airless oven) or inside the top left of the electronics enclosure for a Maxum II Modular Oven. The location of the pressure relief valve within the analyzer is shown in Figures 2-1 and 2-2. This valve allows excess air to escape from the pressurized enclosure in order to prevent over-pressurization. Note that in "normal" purge mode, the relief valve may not open. This is due to small amounts of air that may escape from other points and is not a problem as long as adequate positive pressure is maintained. Note the old and new style valves shown below. The new valve is shown with the exhaust diffuser on top of the analyzer. It is designed with downward-facing holes and a metal screen to prevent dust and other foreign material from accumlulating in the relief-valve exit port. Old Pressure relief valve, MAA (Inside Detector Compartment) Old Pressure relief valve, MMO (Inside Air Input Panel) New Pressure relief valve, MAA and MMO (mounted on top left of electronics enclosure) Figure 2-10 Pressure Relief Valve for PY Purge Manual, August 2017, A5E Rev 8 25

26 Safety Systems - Purging 2.3 Electronics Purging System (with Automatic Purge Unit) 2.3 Electronics Purging System (with Automatic Purge Unit) Overview The Automatic Purge Unit (APU) is optional and used in locations where it is desired to supply power to the system only when the electronics enclosure is properly purged. Power and all other external wiring that enters the Maxum II is disconnected by the APU whenever purge is lost. This is referred to as purging with Type X pressurization (px). The APU is available in Maxum II Airbath/Airless Oven and the Maxum II Modular Oven configurations. The APU purging system consists of the components described in the following sections. 3XUJH $LU 5HJXODWRU 8QVZLWFKHG 3RZHU 6ZLWFKHG 3RZHU 3URSRUWLRQDO 9DOYH &RQWURO 3RZHU 'LVFRQQHFW 5HOD\ &RQWURO $38 3XUJHG JDVVHV H[LWLQJ HQFORVXUH,QVWUXPHQW $LU 6XSSO\ 3XUJH 6WDWXV,QGLFDWRU 3XUJH %\SDVV 6ZLWFK 3XUJH DLU HQWHULQJ HQFORVXUH 6ZLWFKHG 3RZHU WR 3(&0 '& 3RZHU 'LVFRQQHFW 5HOD\ Figure /(*(1' 3RZHU &RQWURO $LU 6XSSO\ $LU )ORZ APU System Component Layout (Modular Oven model) Manual, August 2017, A5E Rev 8

27 Safety Systems - Purging 2.3 Electronics Purging System (with Automatic Purge Unit) Purge Air Inlet and Regulator This is a pressure regulator with air input that is connected to an instrument air source. The regulator is necessary to ensure that the input pressure does not exceed a certain value. Excessive pressure could damage other components in the purging system. The air is connected to the electronics enclosure at the reduced pressure. All instrument air must be clean (free of particulates and flammable vapors) and dry. Air Inlet Figure 2-12 Purge Air Inlet and Pressure Regulator Manual, August 2017, A5E Rev 8 27

28 Safety Systems - Purging 2.3 Electronics Purging System (with Automatic Purge Unit) Proportional Valve This valve provides proportional control of the input air flow. This means that air flow is dependent on the pressure difference between the air inside the electronics enclosure and the ambient outside air (lower pressure difference results in greater flow). Operation of the proportional valve is controlled by the Automatic Purge Unit (APU) which is described below. In the Modular Oven model, the proportional valve is located inside the electronics enclosure on the lower left wall toward the rear. In the Airless/Airbath Oven model,the proportional valve is located in the right, rear, lower section of the electronics enclosure. In this location, it is not visible through the door of the electronics enclosure. It is only accessible via a screw-on access panel. MMO Proportional Valve MAA Proportional Valve Air Input to Electronics Enclosure Maxum Modular Oven Proportional Valve mounted on the inside of the electronics enclosure left wall, lower rear. Control Wiring for Proportional Valve (to APU) Maxum Airless/Airbath Proportional Valve mounted on the outside of the electronics enclosure right wall, lower front. Figure 2-13 Proportional Valve Automatic Purge Control Unit This component is designed to control the purge system of the Maxum II analyzer. The APU monitors the internal and external pressures and sets flow accordingly via the proportional valve. It will also detect when purge pressure is lost and, using the disconnector unit, disable power to the analyzer in the event that proper purging is not present. The APU also controls the process by which power can be reconnected to the analyzer. If power has been turned off on the analyzer, purge pressure must be restored to the electronics zone, and it must be flushed out with fresh instrument air for about 8 minutes before power is connected to remove potentially hazardous levels of flammable gases and vapors from the analyzer before power up. The APU is mounted inside the electronics enclosure of the Maxum II as shown in the following figure. 28 Manual, August 2017, A5E Rev 8

29 Safety Systems - Purging 2.3 Electronics Purging System (with Automatic Purge Unit) Figure 2-14 Automatic Purge Control Unit (APU) shown in Airless/Airbath model Maintenance Switch This device allows a user to override the power cutoff function of the APU for maintenance purposes. This is only allowed when it has been determined that the ambient atmosphere is safe with no flammable gases or vapors. Because operation of the analyzer without proper purge is a potentially dangerous operation, this switch can be operated only by using a key. The maintenance switch allows power to the analyzer to remain connected without purge pressure. This allows qualified personnel to perform applicable maintenance operations which require the electronics enclosure door to be open. The maintenance switch should be set to "normal" at all times unless applicable maintenance is being conducted. The maintenance switch is equipped with an LED that indicates whether the enclosure is properly purged (LED on), in the process of purging (LED blinking intermittently), or whether there is a purge fault (LED blinking). WARNING Potential ignition hazard The maintenance switch should not be set to "maintenance" unless it has been determined that conditions are safe and flammable gases or vapors are NOT present. The maintenance switch should be set back to "normal" as soon as maintenance operations are complete. Failure to observe these precautions could result in severe injury or death. The maintenance switch for the MAA configuration is in the top right corner of the detector compartment, below the electronics enclosure. Manual, August 2017, A5E Rev 8 29

30 Safety Systems - Purging 2.3 Electronics Purging System (with Automatic Purge Unit) Figure 2-15 Location and Close-Up of Maintenance Switch (MAA, Set for Normal Operation) The maintenance switch for the MMO configuration is on the top left of the regulator panel, to the right of the electronics enclosure. Figure 2-16 MMO APU Maintenance Switch Exhaust Diffuser In a properly purged system, all holes including all tubing and wiring entry points are normally sealed closed with metal fittings or silicone sealants. The electronics enclosure door is also normally closed and it is sealed with gaskets. The primary exit path for excess pressure is through the APU to the exhaust diffuser on top of the analyzer. It is designed with downwardfacing holes to prevent dust and other foreign material from accumlulating in the APU exit port. Near the exhaust diffuser is a hollow retaining screw that stabilizes the APU and functions as a vent for the atmospheric reference in the APU. 30 Manual, August 2017, A5E Rev 8

31 Safety Systems - Purging 2.3 Electronics Purging System (with Automatic Purge Unit) Figure 2-17 Covered Purge Exhaust Diffuser Signal Disconnect Relay The Signal Disconnect Relay is mounted externally to the analyzer. This relay disconnects all external wiring to the analyzer except for power to the APU. The Signal Disconnect Relay is controlled by the APU which deactivates the relay when purge pressure is lost. Power circuits are controlled directly by the APU. More than one Signal Disconnect Relay may be installed, depending on configuration. Manual, August 2017, A5E Rev 8 31

32 Safety Systems - Purging 2.4 Maintenance Considerations for Purged Systems Figure 2-18 Signal Disconnect Relays 2.4 Maintenance Considerations for Purged Systems The following practices must be observed in order to operate, maintain and prevent compromise of the Maxum II purging system. WARNING Avoid Equipment Contamination or Ignition of Explosive Gases Failure to correctly observe the following practices may result in a dangerous situation that could lead to severe personal injury or death and/or extensive property damage. 32 Manual, August 2017, A5E Rev 8

33 Safety Systems - Purging 2.4 Maintenance Considerations for Purged Systems EPC Limits The maximum allowable pressure to the EPC is 700 kpa (101.5 psi). In systems without an APU, it is possible to equip the PECM (for Airbath/Airless oven configuration) or PECM-DC (for Modular Oven configuration) with a jumper that will disable the purge alarm (refer to figure below). This jumper must not be used in locations where North American Division 1 and ATEX standards apply. The jumper must not be used without the approval of local safety personnel. Modular Oven Airbath/Airless Oven Figure 2-19 Purge Disable Jumper on PECM or PECM-DC (Shown with Alarm Disabled) In systems equipped with an APU, the Maintenance Switch is intended for use only during maintenance and troubleshooting operations. It is not intended for use during normal operation of the analyzer. This switch must not be left in the "maintenance" position after maintenance is completed. The switch must only be used if the area is known to be nonhazardous. In addition, local safety personnel must approve the use. The electronics enclosure should always be closed in normal operation. Instrument air should be connected and left operational. All instrument air must be clean and dry (free of particulates and flammable gases). During normal startup, fast purge must be allowed to blow through the enclosure, sweeping it free of trapped vapors and gases, for at least 8 minutes. The APU, if equipped, controls the fast purge volume and time. For systems without an APU, the fast purge time must be controlled manually using the fast purge switch. For systems without an APU, pressure inside the enclosure is compared with the pressure outside. A reference tube (see Figure 2-8) is used for this purpose. This tube must not be obstructed. Air does not flow through this tube. The tube is intended to sample the pressure immediately outside the Maxum II enclosure, and it should not be lengthened, shortened, or altered in any way. Manual, August 2017, A5E Rev 8 33

34 Safety Systems - Purging 2.4 Maintenance Considerations for Purged Systems The Maxum II Analyzer should be visually inspected at regular intervals to ensure the integrity of the purge system. The following inspections should be made: Instrument air lines and fittings should be inspected for leaks and damage. All wiring should enter and leave the enclosure through approved conduit fittings or cable glands and should be inspected for wear, cracks, or leaks. All conduit fittings should be inspected to ensure that they are engaged in the threads correctly and are tightened down to necessary tightness. Any unused cable or conduit ports should be sealed closed with approved conduit caps or seals. All cable should conform to local safety code requirements. At startup and whenever maintenance is performed, the electronics enclosure door gaskets should be inspected for wear or damage. The fast purge relief valve should be visually inspected whenever maintenance is performed to ensure that it is free of obstructions or damage. It is possible to verify operation of the purging system. When the analyzer is operating normally verify that the installation area is free of flammable vapors and gases and then open the electronics door to release purge. For analyzers equipped with an APU, power to the analyzer should be immediately disconnected by the APU. For analyzers where purge is monitored by the PECM or PECM-DC, the Purge LED on the front door of the Electronics Enclosure should blink. In systems equipped with an APU, the APU is programmed by the factory with volume information specific to the Maxum II analyzer. Replacement APUs should be ordered only though Siemens. The APU should not be reprogrammed except by authorized personnel. For certified cable glands, care should be taken to comply with any special conditions for safe use listed in the cable gland certificate. 34 Manual, August 2017, A5E Rev 8

35 Safety Systems - Oven General Oven Information Chromatographic separations of samples are carried out inside the oven zone of the Maxum II analyzer. For most separations to be performed, the oven must be kept at an elevated temperature. This means that it must be heated from a hot source while simultaneously ensuring that the source cannot ignite flammable vapors which might be present within the oven. This is accomplished by the oven heater system. A variety of oven configurations are available for the Maxum II. For isothermal (single set temperature) analyses air bath, airless, and modular ovens are available. Since the Maxum II is capable of performing analyses simultaneously on multiple trains (parallel chromatography), the air bath oven is available as either a single oven or as a split oven configuration that offers two independent temperature zones. The air bath oven heats by convection. The airless oven heats by radiation and is available in the split configuration. For configurations requiring only one airless oven, the second oven compartment is left unequipped. The modular oven functions in a manner similar to the airless oven, heating by radiation. Either one or two independent modular ovens may be equipped in a Maxum II Modular Oven analyzer. It should be noted that there may be desired operating conditions which are mutually incompatible. It is possible to desire to perform an application which requires a very hot oven temperature (for example, the separation of very high molecular weight hydrocarbons or the analysis of some heavy liquid chemicals). It is also possible that there may be flammable gases and vapors present in the area of installation which can ignite at relatively low temperatures (for example, some hydrocarbons). Because of these opposing constraints, it is possible to desire an application which requires an oven temperature so high that the analysis zone itself becomes capable of ignition. This situation is not permitted. It is the responsibility of the user to ensure that the analyzer is never installed in an area that is not rated appropriately for the oven temperatures required for the application. Oven temperature is controlled by a resistance temperature device (RTD) sensor and other circuitry. This circuitry maintains oven temperature at the software controlled set point. Within the oven the highest temperature is found on the heater surface and this temperature is limited in different ways depending on configuration. In the airbath/airless oven configuration, the heater temperature is limited by two set point resistors. These set point resistors are generally located on the Power Entry Control Module (PECM). However, set point resistors for the oven heaters may also be located on a Detector Personality Module (DPM). Instructions pertaining to this appear in other documentation. However, for reference, a table of highest surface temperatures and area temperature ratings is included at the beginning of this manual. In a modular oven configuration, the heater temperature is limited by the Power Entry Control Module - Direct Current (PECM-DC). Set point resistors are not needed with the modular oven because, by design, oven temperature never exceeds the surface temperature limit for the T4 temperature rating as identified by the table at the beginning of this manual. Thus, regardless of configuration, the oven heater system is designed to ensure that the temperatures of the oven heaters are controlled in a safe manner and do not create a fire hazard. Manual, August 2017, A5E Rev 8 35

36 Safety Systems - Oven 3.2 Isothermal Air Bath Oven Heater System (Single and Split) 3.2 Isothermal Air Bath Oven Heater System (Single and Split) The isothermal air bath oven is the most common oven used in the Maxum II. It is available in single and split configurations to accommodate a wide range of chromatographic applications. Because high temperatures are often necessary in order to carry out chromatographic separations, the isothermal air bath oven heater system is equipped with various safety features that are intended to prevent ignition Purging The air bath oven heater is a purged system. This means that the hot element is located inside an air purged tubular assembly. Clean instrument air continuously flows over the heating element and into the oven. The flowing air ensures that the heater element cannot get too hot. This air flow also works to distribute heat to the oven. The purge air flow is controlled by the Purge Control Module (PCM). An air pressure sense switch on the PCM determines whether air pressure exists in the tubing that supplies air to the heater. If pressure exists, then air is flowing, and the switch is activated allowing the oven heater to be energized. If the switch does not detect pressure, then it remains off, and power is not supplied to the oven heater. Refer to figure 3-1. The air supply to the air bath oven heater system must be free of particulates, clean of any hydrocarbon vapors or other flammable materials, and dry. Air Pressure Sense Switch for Oven Purge Control Figure 3-1 Pressure Switch for Purge Control Module The air pressure switch is connected to the oven air flow using an extension that runs parallel to the oven air flow line. This extension line is equipped with a coil. The coil is necessary in order to create a short delay between the start of air flow and the activation of the pressure switch. This forces the oven heater to purge for a short time before the oven is switched on (much like the purge delay for the electronics enclosure which is described in section 2 of this manual). Refer to figure Manual, August 2017, A5E Rev 8

37 Safety Systems - Oven 3.2 Isothermal Air Bath Oven Heater System (Single and Split) Figure 3-2 Timing Coil for Pressure Switch See also Safety Systems - Purging (Page 17) Temperature Control As mentioned in section 3.1, the temperature of the oven is controlled via an RTD sensor. The temperature of the air itself is controlled via two independent sensors which work with the two set point resistors mentioned in section 3.1 to ensure that all temperatures remain below possible ignition limits. The limits set by these set point resistors determine the "T-rating" of the entire analyzer in any given situation. The sensors are located inside the heater assembly near where the air exits the assembly. The first sensor is a "temperature limit" sensor that detects whether the air has reached a certain limit based on the applicable T-rating. If this temperature limit is reached as indicated by this sensor, then the power to the heater is cut until the temperature falls below the limit point. If the primary sensor should fail, a second "Over Temperature" sensor will activate at a slightly higher temperature. If this happens, then the power to the oven heater is interrupted. Because this sensor should not activate unless there is a mechanical failure of the first sensor, the power to the heater cannot be reactivated without user intervention. See also General Oven Information (Page 35) Manual, August 2017, A5E Rev 8 37

38 Safety Systems - Oven 3.3 Programmed Temperature Air Bath Oven Heater System (Split) 3.3 Programmed Temperature Air Bath Oven Heater System (Split) In chromatographic applications "temperature programming" is used in special situations where incremental increases in column temperature are needed in order to reduce retention time (the time required for separation). In the Maxum II, the programmed temperature air bath oven is a modified version of the isothermal air bath oven. The primary modification is the addition of a "deflector assembly" in the center of the oven (refer to figure 3-3). This deflector assembly is a partially enclosed chamber that acts as a much smaller oven compartment which can be heated and cooled quickly. Oven Air Input (from Heater) Temperature Probe Deflector Assembly (Cover Not Shown) Figure 3-3 Programmed Temperature Air Bath Oven (with Deflector) The chromatographic column is mounted in the center of the deflector assembly along with a temperature sensor. The heated oven air from a standard air bath heater assembly flows into a hole in the center of the deflector. The interior shape of the deflector allows the temperature of the air around the column to be carefully controlled. The interior shape and small size of the deflector compartment allow the temperature surrounding the column to be modified very quickly such that temperature programming can be used. Within the Maxum II, temperature control and air purging of the air bath heater is the same for the programmed temperature oven as for the isothermal air bath oven. 38 Manual, August 2017, A5E Rev 8

39 Safety Systems - Oven 3.4 Isothermal Airless Oven Heater System (Split) 3.4 Isothermal Airless Oven Heater System (Split) The Maxum II airless oven is used to provide a very stable isothermal oven temperature without the need to supply oven air to the analyzer. This allows for excellent chromatographic results while reducing utility costs. The interior of the airless oven is surrounded with heavy aluminum walls that are embedded with two cartridge heating elements and temperature sensors. The walls radiate heat to the oven air. The airless oven comes configured as two fully independent ovens with separate oven doors (refer to figure 3-4). Note: If only one airless oven compartment is required, then the second compartment is left unequipped without the aluminum walls and heating elements. Figure 3-4 Airless Oven The primary explosion safety system within the Isothermal Airless Oven is the heating and temperature control system. As mentioned above, the oven is heated using two heating elements embedded in explosion-proof channels within the aluminum walls. The temperature of these heating elements is detected and limited by two RTD probe sensors that are also embedded within the aluminum walls adjacent to the heating elements. These probes are controlled by temperature control circuitry on the Power Entry Control Module (or Detector Personality Module) and are set below the applicable T-rating such that exposed surfaces will not exceed the maximum allowable temperature. The locations of the temperature probes and heating elements are shown in Figure 3-5. Manual, August 2017, A5E Rev 8 39

40 Safety Systems - Oven 3.4 Isothermal Airless Oven Heater System (Split) Channel for Heating Element Insert Location for RTD Probe (Same as on Opposite Side) Figure 3-5 Location of Temperature Probes and Heaters on Airless Oven The heating elements are enclosed in hollow tubes running diagonally down the side of the aluminum casing. The heating elements are inserted in the tubes from the top. During operation, the open ends of the heating element tubes (which can be seen in Figure 3-4) are equipped with screw-in, heat-retaining, explosion-proof plugs (figure 3-6) which prevent flammable gases from contacting the hot surface of the heating element if the oven door is opened. These plugs must be fully screwed in such that the threads are fully engaged. Figure 3-6 Heat Retainer Plug for Airless Oven 40 Manual, August 2017, A5E Rev 8

41 Safety Systems - Oven 3.5 Maintenance Considerations for Air Bath and Airless Ovens 3.5 Maintenance Considerations for Air Bath and Airless Ovens The following practices must be observed in order to operate, maintain and prevent compromise of the airbath oven (including programmed temperature oven) and airless ovens of Maxum II. Modular ovens are described in the next section. It must be ensured that the analyzer T-rating is suitable for the area in which the analyzer is to be installed. If a particular application requires oven temperatures that are very hot, it may be necessary to locate the analyzer in a different area of the plant that has a better T- rating. It is the responsibility of the user to ensure that the actual, final analyzer T-rating is suitable for the area of installation. Please refer to the table at the beginning of this document. Instrument air supplied to the air bath oven of the analyzer must be clean and dry as described above. Unsuitable air may cause smoke or other damage to the analyzer and can result in a hazardous condition. The set point resistors used to control the T-rating must have the correct value for the desired T-rating. These resistors are installed at the factory and should be changed only by properly trained service personnel. If these resistors are the wrong value, it could be possible for temperatures within the oven to become too hot for the stated T-rating of the analyzer. For the air bath oven, the heater apparatus should be inspected for physical damage. If there are any cracks, bends or other damage, the assembly must be switched off immediately and replaced. All fittings and conduit attachments must be tight and installed according to local codes. It is possible for heater elements to burn out. The expected life of the heater element is generally 2 years or more for isothermal applications; however, it may be shorter in programmed temperature applications. For the air bath oven, if the heater is to be replaced, the factory spare part is a complete sealed system. For the airless oven, it is possible to replace only the heating element. In either case the new heater must be installed using proper techniques as required locally to ensure that conduit fittings are tightened correctly, that all wiring is reinstalled correctly, and that all pneumatic fittings are attached correctly. This process should be supervised by persons knowledgeable about local electrical and fire safety practices. The oven heater used within the air bath oven is a sealed and closed assembly. It cannot be disassembled for repair in the field. If the heater element or any attached components fail, the entire heater assembly must be replaced with a new replacement part from the factory. Manual, August 2017, A5E Rev 8 41

42 Safety Systems - Oven 3.6 Modular Oven Heater System 3.6 Modular Oven Heater System The Maxum II Modular Oven is used to provide a stable isothermal oven temperature for certain lower temperature applications. This allows for excellent chromatographic results at a greatly reduced product cost and simplified and low cost operation and maintenance for the applicable range of applications. The hardware of the Maxum II Modular Oven analyzer configuration is simplified and fully modular in design. Two independent ovens may be installed in the Maxum II Modular Oven analyzer. Each of these may be a smaller or larger oven as shown below. The ovens are designed such that pre-configured application modules may be easily installed and removed. The image below shows a double application module in the right (large) oven and no module installed in the left (small) oven. Visible in the left oven below is the manifold upon which the application module mounts. The large oven has a double manifold and may alternatively have two single sized application modules installed instead of the double size module shown. In normal operation, the modular ovens are sealed with face plates (not shown) that are attached using thumb screws. Figure 3-7 Typical Modular Oven Configuration The oven heater system of the modular oven consists of two types of heaters. The first is an ambient control heater element mounted in a small manifold in the bottom rear of the oven. This heater element is used to maintain the temperature inside the oven near the desired temperature for measurement, regardless of the ambient temperaure outside the oven. The second type of heater is the analytical heater element that is mounted in the manifold upon which the application module is mounted. This heater element is used to maintain the temperature inside the application module at the desired temperature for measurement. A small modular oven has one analytical heater element and a large oven has two analytical heater elements (on for each side of the manifold). Although they are mounted within manifolds inside of the modular oven, the heater elements are installed in tubes that extend down from the electronics enclosure (EC) as shown in the figure below. These tubes are separated from the oven by the aluminum walls of the manifolds. In this way, the heaters are installed in such a way they are, in effect, part of the EC. As such, they are prevented from being an ignition source by being contained within the purged area. Temperature for the modular oven heater system is detected and limited by RTD probe sensors that are also embedded in tubes that extend down from the EC. These tubes run adjacent to the tubes for the heater elements. These probes are controlled by temperature control circuitry on the Power Entry Control Module - Direct Current (PECM-DC). These circuits are also controlled by over-temperature circuitry on the PECM-DC to prevent exceeding the maximum allowable temperature. The oven heater system of the Maxum II Modular Oven never exceeds the surface temperature limit applicable to a T4 temperature rating. 42 Manual, August 2017, A5E Rev 8

43 Safety Systems - Oven 3.7 Maintenance Considerations Modular Ovens Figure 3-8 Heater and RTD Tubes for the Modular Oven 3.7 Maintenance Considerations Modular Ovens The following practices must be observed in order to operate, maintain and prevent compromise of the Maxum II Modular Oven heater system. The installaion of the heater elements and RTDs should be inspected to verify that they are fully inserted into the tubes as shown in the previous section. Heater wiring should be inspected for any damage and proper connection to the PECM-DC. Application modules should be properly installed with their cover plates, and the face plate of the modular oven should be installed and secured with the provided thumb screws. Because of the relatively low operating temperature, low power, and stable temperature applications, the expected life of the heater elements is expected to be many years. However, if a heater element burns out, replacement is possible. The new heater must be installed using proper techniques to ensure that the heater is re-installed correctly. This process should be supervised by persons knowledgeable about local electrical and fire safety practices. Manual, August 2017, A5E Rev 8 43

44 Safety Systems - Oven 3.7 Maintenance Considerations Modular Ovens 44 Manual, August 2017, A5E Rev 8

45 Valves, Detectors, and External Systems Heated Siemens Liquid Injection Valve (SLIV) SLIV Functional Description Some applications require the use of a heated Siemens Liquid Injection Valve (SLIV) which is shown in figure 4-1. This valve is generally mounted through a side wall of the analyzer oven (refer to figure 4-2). The narrow portion of the valve that extends into the oven is known as the vaporizer. This is where the sample is injected and vaporized at an appropriate temperature based on the boiling point of the sample. The temperature within the vaporizer can be set independently of the oven temperature using an electrical heating element. The temperature limit and over temperature limit of the SLIV heater is controlled by set point resistor modules on the Detector Personality Module (DPM). This temperature limit and over temperature circuitry works in the same way as the temperature control circuitry described in previous sections for the oven heater systems. The maximum temperature that the circuitry allows the valve to achieve is a factor in determining the overall T-Rating for the analyzer in the same manner as the oven temperature limit resistors. Although the SLIV heater is installed in the oven wall, (refer to figures 1-1 and 4-2), it is installed inside an assembly that limits air passage. The interior of the assembly is connected to the electronics enclosure using a conduit pipe (figure 4-3) which contains the electrical wiring for the heater. This conduit and enclosed assembly effectively make the SLIV heater assembly part of the purged electronics enclosure. As described in section 2 of this manual, this creates a higher pressure area inside the SLIV heater assembly which prevents flammable vapors and gases from entering the SLIV heater. The heater assembly is equipped with a flame-arresting vent coil (figure 4-3) that allows purge air to flow through the heater assembly. Figure 4-1 Siemens Liquid Injection Valve Manual, August 2017, A5E Rev 8 45

46 Valves, Detectors, and External Systems 4.1 Heated Siemens Liquid Injection Valve (SLIV) Figure 4-2 Siemens Liquid Injection Valve (Installed) Uninstalled Heater Heater Installed (with Conduit) Figure 4-3 Heater for Siemens Liquid Injection Valve SLIV Maintenance Considerations The Siemens Liquid Injection Valve (SLIV) should be inspected to assure that it is free of physical damage. All tubing and conduit connections should be correctly installed and tightened as prescribed by local safety requirements. Whenever maintenance is performed on the valve, care must be taken not to damage the temperature sensors and the heater element which are inserted in the valve body. 46 Manual, August 2017, A5E Rev 8

47 Valves, Detectors, and External Systems 4.2 Detectors Note that the wiring from the valve temperature sensors to the electronics enclosure must be installed in conduit or connected to intrinsic safety barriers inside the electronics enclosure. In either case, be careful not to damage or alter the wiring. If conduit is in use, a vent coil may be installed near the valve. If this is present it must not be shortened, cut, bent or plugged in any way. It is important that the temperature of the SLIV heater does not exceed the temperature limit. If a vaporization temperature is necessary that is higher than the T-rating, then it may be necessary to locate the analyzer in a location with an appropriate T-rating. Note that the wiring from the SLIV heater to the electronics enclosure must be installed in conduit while inside the oven (refer to figure 4-3). A vent coil will be installed on the SLIV heater near the wiring (refer to figure 4-3). This vent allows the heater to purge. The coil is a flame arrestor and as such it must not be shortened, cut, bent or plugged in any way. WARNING To prevent temperatures that exceed the maximum temperatures specified by the T-rating, the set point resistors for over-temperature and temperature limit must NOT be changed. If the set point resistors must be replaced, it must be verified that the resistor values for the replacement parts are correct. 4.2 Detectors Detector Functional Descriptions In order to analyze the chemical compositions of different samples, four major types of detectors are used in the Maxum II Gas Chromatograph (refer to figures 4-4 through 4-6). The types of detectors are: Explosion Proof/Flameproof Thermal Conductivity Detector (TCD) Intrinsically Safe Thermal Conductivity Detector (ISTCD) Flame Ionization Detector (FID) Flame Photometric Detector (FPD) Valco Pulsed Discharge Detector (PDD) The PDD is manufactured by Valco Instruments and at this time it is not rated for use in hazardous areas. The PDD is currently suitable only for general purpose use (in nonhazardous areas) and for this reason is not applicable to the rest of this section. The Explosion Proof/Flameproof TCD has two variants, one with thermistor bead sensors and one with filament sensors. However, there are no safety related differences between the two variants. Detectors within the Maxum II are housed either in the oven or in the detector enclosure (refer to figures 1-1 and 1-2). Manual, August 2017, A5E Rev 8 47

48 Valves, Detectors, and External Systems 4.2 Detectors The interior of each detector type has active electrical components and/or active flames. These can be sources of ignition that must be prevented from igniting gases or vapors in the analyzer oven or in the area in which the analyzer is installed. For most detectors within the Maxum II, protection is accomplished by enclosing the active elements in a flameproof/explosion proof housing. In these cases electrical, optical and gas connections must penetrate the housing of the detector. All electrical wiring is enclosed in conduit. The conduit is sealed with an approved sealant at the point of entry into the analyzer electrical enclosure. In the case of the FPD a fiber optic bundle penetrates the flameproof housing. This bundle is completely sealed with approved sealants to maintain the flameproof integrity of the main housing. All gases entering each of these flameproof detectors pass through specified lengths of small diameter tubing. Both the total length and the interior diameter of the tubing connections are specified as part of the safety design to serve as flame arrestors. For safety purposes the lengths and/or interior diameters of these tubing connections must not be modified. For the Intrinsically Safe Thermal Conductivity Detector, protection is accomplished by using intrinsically safe circuitry that is designed in such a way that it cannot ignite flammable gases or vapors. This circuitry is equipped on the Intrinsically Safe TCD Detector Personality Module (ISTCD-DPM) installed in the electronics enclosure (refer to figure 1-2). The wiring from the ISTCD-DPM has limited power such that it cannot become an ignition source, even if it becomes shorted. For important information on the safe use of intrinsically safe circuits, refer to the sections of this manual labeled "Intrinsically Safe Devices". All detectors are connected by wiring or fiber optic cable to electronic components within the analyzer electronics enclosure. Safety considerations for those components are described in Section 2 of this manual which covers purging of the electronics enclosure Detector Maintenance Considerations The housing of each flameproof detector should be inspected to insure its physical integrity. There must be no damage including cracks or holes that might compromise the housing. Flameproof detector housings are assembled using threaded covers or a series of bolts which hold various pieces together. These fasteners should all be tightened down correctly to conform to local safety practices. Electrical connections to all detectors should be physically intact. All wiring should be in good condition without wear and any conduit fittings should be tightened to conform to local safety practices. The optical bundle on the FPD should be snugly attached. All gas connections for flameproof detectors pass through tubing of a specified length and internal diameter which is installed at the factory. The length and internal diameter of these tubing connections allow them to serve as flame arrestors. This tubing should never be cut or shortened or bypassed in any way since this will compromise the safety of the detector. The different flameproof detectors have different numbers of tubing connections. However, each tube on each flameproof detector is specifically a part of the safety system. Whenever maintenance is performed on any detector, ensure the correct replacement of all electrical and gas connections at the time of reassembly. This should be done under the supervision of persons trained in explosion prevention practice. 48 Manual, August 2017, A5E Rev 8

49 Valves, Detectors, and External Systems 4.2 Detectors The circuits for the IS-TCD require special considerations to ensure that the circuit remains intrinsically safe. For important information on the safe use of intrinsically safe circuits, refer to the sections of this manual labeled "Intrinsically Safe Devices". Figure 4-4 Explosion Proof/Flameproof Thermal Conductivity Detector Manual, August 2017, A5E Rev 8 49

50 Valves, Detectors, and External Systems 4.2 Detectors Figure 4-5 Thermal Conductivity Detector Beads on Modular Oven Application Module (Intrinsically Safe TCD) 50 Manual, August 2017, A5E Rev 8

51 Valves, Detectors, and External Systems 4.2 Detectors Figure 4-6 Flame Ionization Detector (without Insulation and Cover) Figure 4-7 Flame Photometric Detector (without Insulation and Cover) Manual, August 2017, A5E Rev 8 51

52 Valves, Detectors, and External Systems 4.3 Air Treater 4.3 Air Treater Air Treater Functional Description To provide clean air for the Flame Ionization Detector (FID), the Maxum II uses a catalytic device known as an Air Treater (figure 4-8) to remove hydrocarbons from ordinary plant instrument air. The Air Treater is an independent unit mounted near the Maxum II. It consists of an extremely hot combustion chamber and a catalyst. Instrument air flows through the combustion chamber and interacts with the catalyst to burn any hydrocarbons in the air. The resulting clean air and any formed water vapor are then delivered to the analyzer detector system. The FID is an extremely sensitive sensor of hydrocarbons. It uses a flame as part of the sensing system. This flame burns hydrogen fuel mixed with air. Because the FID is so sensitive, the air used in the combustion process must be completely free of hydrocarbons. Otherwise noise appears on the detector signal. For this reason, the Air Treater is used to remove any trace hydrocarbons. The combustion chamber of the Air Treater is housed in an insulated explosion proof enclosure. This enclosure prevents hot surfaces from contacting the atmosphere in the area of analyzer installation. The Air Treater is connected to electrical power by means of wiring installed in approved conduit. Wiring connections are not supplied by the factory and must be made in the field. The instrument air flows into and out of the explosion proof enclosure through specified flame arrestors. These flame arrestors are supplied by the factory and are firmly attached to the Air Treater assembly. Figure 4-8 Air Treater 52 Manual, August 2017, A5E Rev 8

53 Valves, Detectors, and External Systems 4.4 Methanator Air Treater Maintenance Considerations The Air Treater must be inspected regularly for any physical damage. It must be handled carefully and not dropped or damaged in any other way. If it is damaged it must be replaced. The Air Treater is not designed to be repaired in the field. If it is damaged or becomes inoperable, maintenance is limited to replacement of the unit. The electrical power connections to the Air Treater must be made with wires installed in conduit or connected through cable glands using practices that conform to local safety requirements. All conduit and wiring connections must be tightened and made according to local practice. The completed installation must be inspected by personnel trained in safety practices. The instrument air connections must always be made through the attached flame arrestors. Never remove flame arrestors. If they become damaged, the Air Treater must be turned off until it can be replaced or repaired by the factory. The Air Treater must be firmly mounted to the wall, the floor, or a rack on which the analyzer is mounted. Install the Air Treater so that it cannot be damaged during normal maintenance operations. 4.4 Methanator Methanator Functional Description The methanator is used with a Flame Ionization Detector (FID) when it is necessary to detect carbon dioxide (CO 2 ) or carbon monoxide (CO). In the methanator CO 2 and CO are chemically changed to methane using excess hydrogen and a catalytic reaction. The concentration of methane, which can be detected using an FID, is proportional to the concentration of CO 2 and CO. In this manner, it is possible to detect CO 2 and CO using an FID. The methanator design consists of a stainless steel pipe that is filled with a catalyst. The pipe is heated using heating cartridges, and an RTD temperature sensor is used to regulate heating. The pipe is heated to approximately 400 C and the sample with hydrogen carrier is passed through the pipe. The CO 2 and/or CO (depending on the exact temperature) are converted into methane for detection by the FID. Two versions of the methanator exist for use in the Maxum. The original is protected by purging/ pressurization. The more recent version is protected in an explosion proof enclosure. Both versions are designed to install in the detector enclosure of the Maxum II Airbath/Airless Oven configuration (refer to figure 1-1). (Purged Methanator) - Although the purged/pressurized methanator assembly is installed in the detector compartment, it is installed inside a protective cover that limits air passage. The interior of the assembly is connected to the electronics enclosure using a conduit pipe which contains the electrical wiring for the methanator. This pipe and the protective cover over the assembly effectively make the interior assembly part of the pressurized electronics enclosure. Manual, August 2017, A5E Rev 8 53

54 Valves, Detectors, and External Systems 4.4 Methanator As described in section 2 of this manual, this higher pressure area prevents flammable vapors and gases from entering the methanator. WARNING When the purged/pressurized version of the methanator is installed, if the purge air supply of the Maxum II is interrupted during operation, it is imperative that the analyzer be powered down. Once powered down, the electronics enclosure door must be kept closed for at least 30 minutes. A 30-minute delay is necessary to give the methanator time to cool down sufficiently. If the door to the electronics enclosure is opened prematurely, explosive gas or vapor can ignite by entering the electronics enclosure and then entering the methanator through the conduit tube. Never open the door when explosive gas or vapor is present unless the methanator has had sufficient time to cool down. Figure 4-9 Purged Methanator (Explosion Proof Methanator) The more recent version of the methanator is designed with an explosion proof/flameproof enclosure as described in the Definitions section of this manual (section 1.9). This design eliminates the need to maintain a pressurized methanator enclosure as well as reducing some of the necessary safety measures required for maintenance of the Maxum II when a methanator is installed. 54 Manual, August 2017, A5E Rev 8

55 Valves, Detectors, and External Systems 4.4 Methanator Figure 4-10 Explosion Proof Methanator (Both Versions) As protection measure, the gas inlets and outlets that enter and leave the methanator are configured as flame arrestors (refer to figure 4-8 and 4-9). In addition, both versions of the methanator assembly are insulated to prevent the surface temperature of the methanator from exceeding 180 C (surface temperatures for the explosion proof/flameproof methanator are significantly lower than 180 C) Methanator Maintenance Considerations (Purged Methanator) The methanator should be inspected regularly to ensure there is no physical damage affecting the integrity of the protective cover and to verify that the protective cover is fastened securely in place. The conduit pipe should be attached snugly in accordance with local safety practices. Seals for pipe and cover should fit securely to prevent excessive escape of purge air from around the device. (Explosion Proof Methanator) The methanator should be inspected regularly to ensure there is no physical damage to the enclosure and to verify the screw-on cap is fully tightened. (Both Versions) All gas connections must be made through the tubing that is supplied from the factory and is part of the methanator assembly. In addition, tubing connections are equipped that allow purge air to flow through the methanator into the oven. All tubes from the methanator are designed as flame arrestors of specified length and internal diameter. This tubing should Manual, August 2017, A5E Rev 8 55

56 Valves, Detectors, and External Systems 4.4 Methanator never be cut or shortened or bent or bypassed in any way. If there is any physical damage, the device should be shut down until it can be replaced. WARNING The purged/pressurized methanator must not be operated without purge/pressurization unless it has been verified that the area is free of explosive gases and vapors. This includes opening the door to the electronics enclosure for routine maintenance. WARNING The screw-on cap of the explosion proof/flameproof methanator must not be removed unless it has been verified that the area is free of explosive gases and vapors or unless the methanator has been given sufficient time to cool down (at least 30 minutes without power). 56 Manual, August 2017, A5E Rev 8

57 Safe Operation Maintenance Panel Functional Description The software and parameter settings in the Maxum II chromatograph system can be accessed using the PC-based System Manager software and also via a user access display panel that is mounted on the front door of the Maxum II electronics enclosure. Two types of display panel exist, both of which can be used to perform the same user functions. The newest version is the Color Touchscreen display, which is described in section 5-3. The other, described in this section (figure 5-1), is the Maintenance Panel (which is also sometimes called a Human Machine Interface, or HMI). Both are shown below for comparison. The Maintenance Panel consists of an LCD screen, numeric keypad, status LEDs, and various function keys. Most maintenance and operation functions for the Maxum II can be performed using the Maintenance Panel. The Maintenance Panel is the primary means for a user located at the analyzer site to obtain alarm information and purge status of the Maxum II. The Maintenance Panel can be operated whenever power is applied to the Maxum II, even if the installation area contains fire hazards. Of particular importance are the "Purge" and "Power" LEDs located in the top right corner of the panel. If an APU is not installed, the "Purge" LED flashes when purge pressure is lost. The "Power" LED is lit at all times when power is applied to the analyzer. Note that the "Fault" and "Warning" LEDs are related to the trouble reporting systems of the Maxum II but are not applicable to the safety systems. Use of the Maintenance Panel for maintenance and operation functions is covered in the Maxum II Maintenance Manual (Siemens part number ). Figure 5-1 Maintenance Panels - Color Touchscreen (left) and legacy HMI (right) Manual, August 2017, A5E Rev 8 57

58 Safe Operation 5.3 Color Touchscreen Display Functional Description Note In addition to the Maintenance Panel installed on the analyzer, there is an emulator (called HMI emulator) available through the PC-based Gas Chromatograph Portal software. The HMI emulator can perform most of the tasks that can be performed from the physically installed Maintenance Panel. Note Some older analyzers may have a different panel, called Maintenance Panel Level 1, which does not have an LCD screen or keypad. This device consists of a panel of four LEDs mounted on the electronics enclosure door. Of particular importance on the Level 1 panel is the "Purge" LED, which lights when purge pressure is lost. 5.2 Maintenance Considerations for Maintenance Panel No specific field maintenance is required for the Maintenance Panel. If the Maintenance Panel fails it must be replaced. During replacement, care should be taken to prevent damage to the gaskets surrounding the face of the Maintenance Panel (in order to prevent leaking of purge air). 5.3 Color Touchscreen Display Functional Description The software and parameter settings in the Maxum II chromatograph system can be accessed using the PC-based workstation software and also via a user access display panel that is mounted on the front door of the Maxum II electronics enclosure. Two types of display panel exist, both of which can be used to perform the same user functions. The newest version, which is described in this section, is the Color Touchscreen Display. The other, described section 5-1, is the Maintenance Panel (which is also sometimes called a Human Machine Interface, or HMI). The interactive Color Touchscreen Display is mounted on the analyzer door with a series of status LEDs located to the right of the display. Most maintenance and operation functions for the Maxum II can be performed using this display. The Color Touchscreen Display is the primary means for a user located at the analyzer site to obtain alarm information and purge status of the Maxum II. The display can be operated whenever power is applied to the Maxum II, even if the installation area contains fire hazards. Of particular importance are the "Purge" and "Power" LEDs located to the right of the display. If an APU is not installed, the "Purge" LED flashes when purge pressure is lost. The "Power" LED is lit at all times when power is applied to the analyzer. Note that the "Fault" and "Warning" LEDs are related to the trouble reporting systems of the Maxum II but are not applicable to the safety systems. 58 Manual, August 2017, A5E Rev 8

59 Safe Operation 5.4 Maintenance Considerations for Control Interface Module Display Use of the display for maintenance and operation functions is covered in the Maxum II Reference Manual and the Maxum II Reference Manual, Modular Oven Configuration. Note In addition to the display installed on the analyzer, there is an emulator (called HMI emulator) available through the PC-based workstation software. The HMI emulator can perform most of the tasks that can be performed from the physically installed display. Figure Color Touchscreen Display Maintenance Considerations for Control Interface Module Display Other than screen cleaning, no specific field maintenance is required for the display. If needed, use a soft lint-free cloth dampened with isopropyl alcohol to clean the touch screen. Do not use any sharp object to operate the touchscreen, as this may damage the covering. If the display fails it must be replaced. During replacement, care should be taken to prevent damage to the gaskets surrounding the face of the display (in order to prevent leaking of purge air). The display is constructed of tempered glass with a durable plastic covering. If the display is damaged, it is recommended that it be replaced for optimum use. However, unless the damage causes leaking of purge air, the safety certification of the analyzer should not be compromised. Connection circuitry to the display is designed to be intrinsically safe. Special considerations are required to maintain this level of protection. For important information on the safe use of intrinsically safe circuits, refer to the sections of this manual labeled "Intrinsically Safe Devices". Manual, August 2017, A5E Rev 8 59