mtc001 Thermocouple Converter

Transcription

1 THERMOCOUPLE CONVERTER 1-WIRE INTRINSICALLY SAFE mtc001 mtc001 Thermocouple Converter Document No , Revision A February CMC Industrial Electronics Ltd.

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3 mtc001 Thermocouple Converter Technical Manual /i Table of Contents Revision 1, May 9, ii 1. Overview Description of Indicators Installation Planning the installation Planning the network layout Wiring the converter Communications Decoding the Converter Data Word Service Service access Troubleshooting a completely inoperative network Incorrect temperature readings Specifications Appendix 1 - Installation Drawings Table of Figures Figure 1 - Illustration of Indicators... 3 Figure 2 - Typical Network Layout... 7 Figure 3 Enclosure wiring details... 9

4 mtc001 Thermocouple Converter Technical Manual /ii Revision Notes Revision -, May 9, 2006 First release Revision A, February 15, 2007 Update illustrations

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6 mtc001 Thermocouple Converter Technical Manual /1 1. Overview The mtc001 Thermocouple Converter converts 21 type T thermocouples to scaled temperature values. It is designed to measure the temperature of thermocouple cable used for temperature measurement in bulk storage bins for grains and other commodities. Ultra low power technology is used to allow operation on CMC Industrial Electronics deployment of the Dallas 1-Wire bus for intrinsically safe locations. When used with the mbc081 Bus Converter the device is Intrinsically Safe. The unit includes 3 bus cable 110 connectors with branch disconnect switches simplifying service of the installed system. The microvolt outputs of the thermocouples are scaled to degrees Celsius. Full temperature compensation is provided. The unit measures temperatures from 60 o C to +400 o C in 1 o C increments with an accuracy of ±2 o C. The unit incorporates 3 level high voltage ESD protections on the thermocouple input leads.

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8 mtc001 Thermocouple Converter Technical Manual /3 2. Description of Indicators Bus Data Present Bus Power Present Status Figure 1 - Illustration of Indicators The converter requires no settings. There are 3 indicator lamps: Description Color Operation Bus Power Red 5 volt DC power on Bus Data Green Flashes if bus data is present Status 1 flash Active no communications with bus converter 2 flashes Active with communications with bus converter 3 flashes open wire detection in progress 4 flashes performing startup self tests 5 flashes cold reference sensor fault 6 flashes unable to read serial number 7 flashes power on test failed 8 flashes - calibration table corrupted 9 flashes firmware test failed

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10 mtc001 Thermocouple Converter Technical Manual /5 3. Installation Careful planning of the system installation will ensure reliable operation. Installation of this system should be planned and executed by licensed electricians familiar with installations in hazardous area locations. A local regulatory authority, trained in the inspection of hazardous area electrical systems, should inspect the completed installation. 3.1 Planning the installation *** IMPORTANT SAFETY NOTICE *** This system is intrinsically safe. Follow the drawings in the mbc081 Bus Converter Technical Manual exactly to ensure the system remains intrinsically safe. No other cables of any kind may share the network cable conduit system. Placing other cables in the conduit or device enclosures will defeat the intrinsic safety system. Failure to observe the supplied drawings and instructions could result in a fire or explosion and the risk of personal injury or death. This device must be connected to a good quality electrical system ground through the conduit system and its metal enclosure. The converter incorporates high-energy lightning protection that is shunted to earth ground. Failure to properly ground the metal enclosure using a metallic conduit system and metal mounting bracket may cause severe internal damage to the device in the event of a high voltage transient signal on the thermocouple cable inputs. To be effective, hazards monitoring systems must provide reliable readings. The environment where these systems are installed can be severe and requires rigorous planning to achieve a reliable, effective system. The following general guidelines should be followed when planning your installation: 1. Do not mount the converters where they will be directly exposed to weather. This includes rain, snow and direct sunlight. They do not need to be mounted in a second enclosure, but do need a simple shield to protect them from direct exposure to the weather; 2. Mount the converters where they can be easily serviced; 3. Use only metallic conduit for the wiring system; 4. For conduits that enter the bin space ensure that gas tight connections and fittings are used. Bulk products are treated with corrosive pesticides including phosphine gas that can damage electronics, and corrode copper wiring. It is imperative that these corrosive gases be kept out of the converter enclosure; 5. Ensure the enclosure of the converter is mounted to a metal mounting surface connected to earth ground. A pre-drilled metal mounting bracket, part no mtc001-mb, is available to assist in mounting the converter.

11 mtc001 Thermocouple Converter Technical Manual /6 Observing these basic guidelines will ensure the system is reliable and easily serviced. 3.2 Planning the network layout The mtc001 thermocouple converter is both a device and junction point for the 1-Wire network. The system is wired using CAT5 cable in a fully metallic conduit system. Shielded cable is not required. Do not use plastic or non-metallic conduit systems to install this system. The thermocouple lead wire form the converter to the start of the supported bin cable also must be installed in a metallic conduit system. Use gas tight fittings inside the bin and a packed EYS fitting where the cable exits the bin. If possible purchase the thermocouple cables with sufficient lead wire so that no junctions are required. Metallic flex conduit, installed using weather tight connectors, is permitted. A single RJ-11 jack is provided at each converter for connecting a mbc081 Bus Converter to the network. This connection does not have to be at the start of a network. If a bus converter is connected to the device, do not use the INCOMING punch down connector. Extend the network using the BRANCH A and BRANCH B punch downs. For all other devices, the cable from a branch punch down on a previous device connects to the INCOMING punch down on the next device. Again the network is extended using the BRANCH A and BRANCH B punch downs. Extend the network using the BRANCH A punch down first. Figure 3 details a typical 1- Wire network layout. Plan your network carefully. Limit the number of tees if possible. The maximum CAT5 cable length is 1000 feet. If the RJ-11 connector on the terminal board is not used for a Bus Converter, it may be used to connect any approved CMCIEL sensor to the network. The mtc001 will operate on a mixed network of approved sensors and occupies only one device address. The maximum number of addressed devices on a single mbc081 Bus Converter is 32.

12 mtc001 Thermocouple Converter Technical Manual /7 Safe Area Hazardous Area moi215 mbc081 mbc081 mbc081 Use EYS fittings if required by code or corrosive gasses present Internet / Intranet CAT5 wiring enclosed in metallic conduit or sheilded CAT5 cable in non-metallic conduit Desktop Computer Type T Thermocouple cable 21 channels Type T Thermocouple cable 21 channels Use gas tight fittings if corrosive gases present Type T Thermocouple cable 21 channels Type T Thermocouple cable 21 channels Figure 2 - Typical Network Layout

13 mtc001 Thermocouple Converter Technical Manual /8 3.3 Wiring the converter *** IMPORTANT NOTICE *** The electronics used in this product are sensitive to static discharge. Do not handle the upper electronics module without observing industry standard static discharge procedures. These include the use of personnel grounding straps in high static areas. Do not remove the electronics module from its static protected packaging until all wiring is completed and verified. Handle the module by its edges and do not handle unnecessarily. If the module is removed for service, return it immediately to the supplied antistatic packaging for transportation. Failure to properly handle the module may result in permanent damage. Before wiring the converter, punch all conduit entry holes and physically mount the converter s enclosure. Use the provided template to punch the holes. Do not punch unused holes. It is recommended that the enclosure be mounted using the mtc001-mb mounting bracket. The enclosure must be mounted to a grounded metal bracket. Remove the terminal board assembly from its packaging. The terminal assembly is not static sensitive. Mount the terminal board in the enclosure using the supplied self-tapping screws. The terminal board is mounted with the cable clamps closest to the conduit entries. The converter is wired using 110 punch down terminals for the 1-Wire network. The thermocouple cables are connected to screw terminals. Figure 2 details the network and thermocouple cable connections. If shielded cable is used, connect the shields using the provided clamps and screw terminals. Only the first device should have the cable shields connected to earth ground. A jumper is provided on the terminal board to connect the shielding system to earth ground. Install this jumper only on at the first device directly connected to the mbc081 Bus converter. Connect the network cables using an approved 110 punch down tool. Using a screwdriver or other non-approved tool will permanently damage the punch down terminals. Follow the color code for CAT5 cable on the terminal board. The thermocouple cables are arranged as up to 3 groups of 7 thermocouples. Each group has a single constantin (silver colored wire) and up to 7 copper wires. Many different cable configurations exist. Follow the color code provided for the cables you are using. Unused inputs should be left open. Thermocouples sharing a constantin wire must connect to the same terminal block. Unused channels can be disabled by installing a jumper block on the header next to the thermocouple terminal blocks. Connected channels must have the jumper blocks removed. Once the wiring is complete and verified, remove the upper electronics module from its antistatic packaging. Immediately install the module and secure using the 5 screws provided. Follow the Important Notice instructions above whenever handling the electronics module. Ensure any used network branches have their branch disconnect switches turned on.

14 mtc001 Thermocouple Converter Technical Manual /9 Install the enclosure cover using the 6 Phillips screws supplied. Ensure the cover gasket it properly placed when installing the cover. Install jumper blocks to disable unused channels Terminals for cable shields. Use supplied clamps to connect shield if present. Connection for the mbc081 Bus Converter or any approved CMCIEL sensor Thermocouples 1-7 Thermocouple Cable Entry Thermocouples 8-14 Branch B Cable Entry Thermocouples Branch A Cable Entry Branch B Branch A Incoming Incoming Cable Entry Use provided template to drill holes. Remove template when finished. Jumper these terminals together only in the enclosure where the mbc081 Bus Converter connects Figure 3 Enclosure wiring details

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16 mtc001 Thermocouple Converter Technical Manual /11 4. Communications The mtc001 Thermocouple Converter is a fully compliant Dallas 1-Wire device. The converter connects to the CMCIEL wiring system using CAT5 cable. A single RJ-11 jack is provided for connecting a mbc081 Bus Converter or other approved CMCIEL 1-Wire device to the wiring system. The converter requires a bus converter to convert the Dallas 1-Wire signaling system to a system recognized by commercial programmable controllers. The Bus Converters provide a Modbus485 RTU interface. CMCIEL manufactures Bus Converters for both commercial and hazardous areas. The Bus Converters will automatically acquire the serial number of the converter on request. As a Dallas 1-Wire device, the converter value is returned using the read scratch function as 3 bytes, the first 2 bytes a signed word containing the multiplexed temperature values and the 3 rd byte the Dallas 1-Wire - 8 bit CRC. The family code for the converter is 177 decimal or B1 Hex. The converter responds to the following Dallas function codes: Code Decimal Code Hex Function 240 F0 Search ROM Match ROM 15 0F Read ROM Read ROM 204 CC Skip ROM 190 BE Read Scratch, 3 bytes, low byte + high byte + Dallas 8 bit CRC Refer to Dallas Semiconductor documentation for complete details on the operation of the Dallas 1-Wire signaling system.

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18 mtc001 Thermocouple Converter Technical Manual /13 5. Decoding the Converter Data Word The output of the converter is a single 16 bit word. The word consists of a 5 bit address, and a 11 bit signed thermocouple temperature. The address occupies the upper 5 bits of the word. The converter provides 23 values over the multiplexed bus. The address and associated value are automatically incremented every 3 seconds. During startup and, periodically for open sensor detection, the incrementing will stop for up to 1 minute. During this time the address will remain on 0 and the status register will indicate the function in progress. The function associated with each address is: Address Value 0 Converter status bits: 2 communications with mbc081 is active 3 open wire detection in progress 4 startup in progress 5 cold reference sensor fault 6 unable to read serial number 7 - power on tests failed 8 -calibration tables corrupted 9 controller firmware corrupted 1 Reference temperature in degrees Celsius 2-22 Thermocouple temperatures in degrees Celsius 2 8 correspond to terminals T/C1 T/C correspond to terminals T/C8 T/C correspond to terminals T/C15 T/C 21 All temperatures are presented as signed 11 bit 2 s complement numbers. To decode the address and data perform the following steps: 1. Create a converter values table consisting of 23 integer registers; 2. Move the received data word to a temporary register; 3. Move the temporary register to a register named the index pointer register; 4. Perform a logical AND with the constant F800 HEX and the index pointer register; 5. Divide the index pointer register by 2048; 6. Perform a logical AND with the constant 07FF HEX and the temporary register; 7. Test bit 10, and if high, logical OR the temporary register with F800 HEX; 8. Move the temporary register using the previously extracted address as an index into the temperature converter values table.

19 mtc001 Thermocouple Converter Technical Manual /14 The above algorithm will automatically populate a table of converter values from the received data word. The converter automatically checks for open cables at startup and every 60 complete cycles, approximately every 15 minutes. Thermocouples found open are set to the temperature 1023 o C. The maximum temperature range of a working thermocouple is from 40 o C to +400 o C. During the cable check, the index value will remain at 0 and the status register will have bit 2 set. When designing a hazards monitoring application it is important to reduce false alarms. False data readings can be caused by a number of conditions including static charge from material moving within bins. To prevent false alarms, the alarming application should employ timers or multiple data point verification before declaring an alarm. The time constants being monitored are typically long and most false alarms can be eliminated using a simple timer scheme.

20 mtc001 Thermocouple Converter Technical Manual /15 6. Service 6.1 Service access To service the converter, remove the 6 Phillips screws and carefully remove the cover. Use care not to tear or deform the gasket. To remove the upper electronics module, remove the 5 Phillips crews securing it to the terminal board. Be certain to remove and replace all 5 screws whenever servicing the module. The bottom center screw is used to thermally connect the upper and lower assemblies to provide ideal temperature compensation. Failure to replace this screw will reduce the converters accuracy during changing temperatures. With the screws removed, grasp the upper assembly by its side edges and pull it straight out. Follow the Important Notice instructions in Section 3.3 whenever handling the electronics module. To re-install the module, locate the 2 connectors and press the module straight in. Again hold the module by its edges. Replace all 5 Phillips screws. 6.2 Troubleshooting a completely inoperative network These instructions assume that the mbc081 is communicating over the RS-485 network to its host and that the network problem is with the 1-Wire network. It is also assumed that the mbc081 has been correctly configured and that the network addresses for the devices have been acquired. If this is the first time the network is being started, the addresses are not required to get the lamps flashing properly. The addresses are required to retrieve data over the network. The mtc001 employs branches disconnect switches to aid in the diagnosis of a completely inoperative network. Follow this procedure for troubleshooting: 1. Remove the cover from the mbc081 serving the network; 2. Observe the 2 status indicators on the mbc081. The red status indicator should be flashing at a once per second rate. The green communication indicator should be flashing verifying communications with the host. If the red lamp is flashing one of the following error codes, the problem is likely with the network cabling or devices: Flashes Description 1 5VDC supply wire shorted to common wire 2 No sensors detected on the bus 3 Data wire shorted to common wire 4 Data wire shorted to 5VDC wire 3. Open the first mtc001 connected to the mbc081 Bus Converter; 4. Observe the network status lamps on the upper electronics assembly. The red power indicator should be on and the green data indicator should be flashing;

21 mtc001 Thermocouple Converter Technical Manual /16 5. If the indicators are flashing properly, observe the status lamp on the mtc001. It should be flashing 2 short flashes. If the lamp is flashing 1 short flash the device is not being addressed by the mbc081. Verify that all of the addresses have been acquired before proceeding. If error codes 5 9 are flashing (see Section 2 for an explanation of codes), the module is defective and should be returned for service; 6. If the network status lamps are not illuminating properly, turn off both branch disconnect switches in this device. The branch disconnect switches are in upper right corner of the enclosure and marked BRANCH A and BRANCH B. On is up (towards the edge of the enclosure); 7. If the lamps resume normal operation the problem is with a device or cabling on one of the disconnected branches. Turn on one switch at a time to determine the defective branch. Continue along the network, using the disconnect switches until the defective cable or electronics module is located. 8. If the lamps do not resume normal operation, replace the upper electronics assembly for this device. If the lamps resume normal operation, the electronics module in this device is defective. If the lamps do not resume normal operation, the mbc081 is defective or the wiring between the mbc081 and this module is damaged or incorrectly connected. 6.3 Incorrect temperature readings If all temperature readings for this module are incorrect, observe the status indicator for the module. It should be flashing 2, 3 or 4 short flashes. If the lamp is flashing 1 short flash the device is not being addressed by the mbc081 and no data is being read from the device. Verify that all of the addresses have been acquired before proceeding. If error codes 3 7 are flashing (see Section 2 for an explanation of codes), the module is defective and should be returned for service. If only some of the readings are incorrect, verify the connections at the thermocouple terminal strips. A process meter capable of reading thermocouples can also be used to verify the integrity of the thermocouple cables. If you do not have a process meter, swap the thermocouple cables between 2 terminal strips. If the problem remains on the same thermocouple numbers, the electronics module is defective. If the problem moves, the cable is defective. If the cable verifies and the reading remains incorrect, replace the upper electronics module.

22 mtc001 Thermocouple Converter Technical Manual /17 7. Specifications Description Sensor bus Voltage Current Communications Characteristic 5 VDC 3.5 ma max 1-Wire Bus Type T Inputs Resolution Accuracy Range 1 o C ±2 o C -60 o C to +400 o C Environment Temperature Relative Humidity -40 to 70 C (-40 to 158 F) 0 to 95% non-condensing Dimensions Length Height Depth 225mm (8.75in) 150mm (5.75in) 60mm (2.25in)

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24 mtc001 Thermocouple Converter Technical Manual /19 Appendix 1 - Installation Drawings The following is a list of the installation drawings in this appendix: mtc001 Thermocouple Converter Bracket Fabrication Details mtc001 Thermocouple Converter Enclosure Details mtc001 Thermocouple Converter Conduit Hole Template

25 mtc001 Thermocouple Converter Technical Manual / NOTES UNLESS OTHERWISE SPECIFIED: 1. ALL DIMENSIONS IN INCHES ± MATERIAL: 14 GAUGE COLD ROLLED STEEL 3. FINISH: POWCHEM P-BK0432S5, BLACK, SMOOTH, SEMI-GLOSS 4. CLEAN UP ALL EDGES 5. TAP HOLES AFTER POWDER COATING Drill and tap for #6-32 screw, note 5 Ø ENCLOSURE OUTLINE REV DESCRIPTION DATE APP. Ø 0.25 Drill and tap for #6-32 screw, note 5 CMC Industrial Electronics Ltd. Burnaby, BC Canada THERMOCOUPLE CONVERTER BRACKET FABRICATION DRAWN BY: REF: DO NOT SCALE D. FORST mtc001 DATE: CHECKED BY: DRAWING NO: REV: MAR 27/06 T. GREENAWAY APPROVED BY: COPYRIGHT 2006 PAGE: 1 OF 1

26 mtc001 Thermocouple Converter Technical Manual / Mounting hole 6 x 32 clearance Maximum screw head size 0.275" Mounting hole 6 x 32 clearance Maximum screw head size 0.275" CMC Industrial Electronics Ltd. Burnaby, BC Canada mtc001 THERMOCOUPLE CONVERTER ENCLOSURE DETAILS DRAWN BY: REF: DO NOT SCALE DMF mtc001 CHECKED BY: DATE: DRAWING NO: REV: MAR 31/06 T. GREENAWAY APPROVED BY: COPYRIGHT 2006 DMF PAGE: 1 OF

27 mtc001 Thermocouple Converter Technical Manual /22 REV DESCRIPTION DATE APP. Not To Scale Use Temp[late Provided with Product 8.20 Top of enclosure with cover off Template adhesive is temporary Remove immediately after cutting holes Align arrow with center screw hole Incoming Network Branch A Network Maximum hole size 0.90" Branch B Network Thermocouple cables Use template to drill conduit holes in enclosure 1.96 Enclosure bottom CMC Industrial Electronics Ltd. Burnaby, BC Canada mtc001 THERMOCOUPLE CONVERTER CONDUIT HOLE TEMPLATE DRAWN BY: REF: DO NOT SCALE DMF CHECKED BY: DATE: DRAWING NO: REV: MAR 31/06 T. GREENAWAY APPROVED BY: COPYRIGHT 2006 DMF PAGE: 1 OF 1 NOTES; 1. FOR USE WITH mtc001 THERMOCOUPLE CONVERTER 2. LABELS TO BE PRINTED ON WHITE PAPER LABEL STOCK 3. LABEL STOCK TO HAVE REMOVABLE ADHESIVE 4. PRINT IN BLACK INK