MicroTech Self-Contained Air Conditioning System

Transcription

1 Open Protocol Data Information Packet Version 2.3 Group: Controls Date: October 1999 MicroTech Self-Contained Air Conditioning System Open Protocol Data Communications t 2002 McQuay International

2 - C O N F I D E N T I A L - This Document may not be copied or reproduced in any way without the express written consent of McQuay International. NOTICE Copyright 1999 McQuay International, Minneapolis MN All rights reserved throughout the world. McQuay International reserves the right to change any information contained herein without prior notice. No guarantees are given as to the accuracy of information provided. Microtech Self-Contained AC System Open Protocol 2

3 Contents Revision History...4 Functional Goals of Open Protocol...5 Overview... 5 Software Identification... 5 Open Protocol Network Configuration...6 Overview... 6 OPM Communications Methods... 6 RMC Unit Communications Method... 7 OPM -- Open Protocol Master Panel...8 System Integrity... 8 Inputs & Outputs...9 Analog Inputs... 9 Digital Inputs... 9 Digital Outputs Description of Operation...12 Operating States Unit Transitions Self-Contained Unit Variables...14 Read Only Memory Locations Read/Write Memory Locations Network Control Features RMC Open Protocol...32 Overview Features of the RMC Panel RMC Variables...34 Read Only Memory Locations Read/Write Memory Locations Interface Development and Testing...37 Required Development Testing Tools Setup of Hardware for Testing Glossary Microtech Self-Contained AC System Open Protocol

4 Revision History Version 2.3 7/99 Airflow status has changed to $045C Documented fan speed ($0436)for units with inverters. Renamed several memory locations Expanded definitions of all points Formatting changes Version 2.2 4/96 This is a general upgrade and format change of the document Version /94 This is a general upgrade and format change of the document. Version 2.0 3/94 References to SnyderGeneral changed to McQuay International. Consolidation of tables and text concerning controller memory locations. Version 1.0 8/93 Initial Release Microtech Self-Contained AC System Open Protocol 4

5 Functional Goals of Open Protocol Overview Software Identification McQuay Open Protocol for Self-Contained Air Conditioning units allows other Building Automation System (BAS) companies to communicate with such units singly or in a network. In addition, useful operating information may be obtained via communication "reads" to the controller, and remote control of the unit is made possible by "writes" of new setpoints and commands to the controller. This Open Protocol document contains information that is applicable only to McQuay Self- Contained Units (SCUs) and Remote Monitoring and Control (RMC) panels that have been programmed with the appropriate software. Prior to establishing any Open Protocol communications, the BAS integrator must verify that the controller's software identification matches the following: "*" designates a wild card; any character in this position is acceptable. Controller SCU RMC Software ID J RMC-E01* The Software ID can be identified via menu 25 on the SCU keypad 5 Microtech Self-Contained AC System Open Protocol

6 Open Protocol Network Configuration Overview This section explains how the McQuay International Open Protocol Network works so that you can choose the correct equipment and program your system to communicate through McQuay International MicroTech Open Protocol. OPM Communications Methods Shown below is a typical Open Protocol Network for SCUs. BAS -- Building Automation System OPM -- Open Protocol Master SCU -- Self-Contained Units Level 1 OPM A BAS B Etc. Level 2 B SCU B SCU The Open Protocol Master (OPM) panel provides a single communications port entry into the McQuay network. Up to 64 Unit Controllers may be accessed through a single OPM panel. The OPM panel consists of a model 120 controller. The BAS communications device connects to Comm port A, which is pre-configured for RS-232, 9600 baud. Port A is the Open Protocol communications port for the BAS communications device. Comm port B is a daisy-chained, multi-drop, 9600 baud RS-485 proprietary McQuay protocol. The Unit Controller is factory mounted and provides pre-programmed, pre-engineered and pre-tested stand-alone control. There is one controller for each unit. The McQuay Open Protocol Monitor Software package is used to configure, commission, and troubleshoot the McQuay communications system. The Microsoft Windows based software contains diagnostic routines that can be used to troubleshoot the McQuay network. The Monitor Software is installed in the IBM or compatible PC, and the PC is connected to the OPM port A as shown: Microtech Self-Contained AC System Open Protocol 6

7 Level 1 OPM A "Monitor" Software B Etc. Level 2 B SCU B SCU The McQuay communications network must be "commissioned" prior to connection to the BAS communications device. Commissioning is typically performed by a representative of McQuay International. Once the McQuay communications network has been commissioned and is totally functional, the Monitor PC can be disconnected and a communicating device from the BAS network installed. The unit controllers continue to operate when communications are lost. However, the network must be intact for read and write requests from the BAS communications device to be passed along to the units. When the Building Automation System's communicating device is connected to the OPM panel, the communications configuration is as follows: Level 1 OPM A BAS B Etc. Level 2 B SCU B SCU RMC Unit Communications Method An RMC panel can be substituted for an OPM panel. However, unlike the OPM, the RMC exercises its own control over the SCUs. Therefore, care must be taken to insure that commands to the individual units from the BAS do not conflict with those from the RMC. 7 Microtech Self-Contained AC System Open Protocol

8 OPM -- Open Protocol Master Panel System Integrity There is only one memory location that can be read in the Open Protocol Master Panel. It is used to verify that the OPM is powered and communicating, and that the applications code is intact. Open Protocol Master Status $ = Program is running 255 = Program is not running Microtech Self-Contained AC System Open Protocol 8

9 Inputs & Outputs Analog Inputs POINT NUMBER 0 Supply Air Temperature 1 Mixed Air Temperature 2 Entering Water Temperature 3 Leaving Water Temperature 4 Return Air Temperature 5 Outdoor Air Temperature 6 Space Air Temperature 7 Economizer Position 8 Compressor #1 Alarm 9 Compressor #2 Alarm 10 Compressor #3 Alarm 11 Compressor #4 Alarm DESCRIPTION 12 Duct Static Pressure #2/Air Velocity 13 Duct Static Pressure #1/Building Static Pressure 14 VIV Position/Motor Amps 15 External Reset/Refrigerant Pressure/Humidity 16 Compressor #5 Alarm 17 Compressor #6 Alarm 9 Microtech Self-Contained AC System Open Protocol

10 Digital Inputs POINT NUMBE R 0 Enthalpy Switch 1 Smoke Detector 2 Water Flow Switch 3 Airflow Switch 4 Filter Switch 5 Freeze Status 6 Heat Fail 7 Duct High Limit 8 System On/Off 9 Cool Enable 10 Heat Enable 11 Manual Off DESCRIPTION 12 High Pressure Switch, Compressor #1 13 High Pressure Switch, Compressor #2 14 High Pressure Switch, Compressor #3 15 High Pressure Switch, Compressor #4 16 High Pressure Switch, Compressor #5 17 High Pressure Switch, Compressor #6 Microtech Self-Contained AC System Open Protocol 10

11 Digital Outputs POINT NUMBE R 0 Alarm DESCRIPTION 1 Compressor #1/Close CW Valve 2 Compressor #2/Open CW Valve 3 Compressor #3 4 Compressor #4 5 Bypass Valve 6 Heat/VAV Output 7 Water & Air Economizer Close/Face & Bypass Close 8 Water & Air Economizer Open/Face & Bypass Open 9 VIV Close/Inverter Slow Down 10 VIV Open/Inverter Speed Up/Dual Motor Switchover 11 Electric Heat #1/Water or Steam Close 12 Electric Heat #2/Water or Steam Open 13 Fan 14 Outdoor Air Damper 15 Fan Operation 16 Compressor #5/Bypass Valve Close 17 Compressor #6/Bypass Valve Open 11 Microtech Self-Contained AC System Open Protocol

12 Description of Operation Operating States An SCU operates in one of several states that may be read from the Unit Status memory location, $043D. Operation in most of these states is described below. The Start Requested State is a short duration transitional state. Calibrate State is a manual state used to commission the unit. Transitions between the states are discussed in the next section. Off In the Off state, fans, cooling and heating are off. All dampers, vanes, and valves are driven closed continuously. Startup Initializing This period of operation allows variable inlet vanes (VIVs) and any valves to come into startup position before the unit starts. The occupancy output is in the closed or occupied position. Relays driven by this output may be used to open internal isolation dampers or to open external smoke dampers before the fan starts. The occupancy output remains in the closed or occupied position for all states except Off. Recirculation This period of operation allows the unit airflow to stabilize before a decision is made to enter a cooling or heating state. When the unit enters this state, the supply fan is turned on. Outdoor air dampers remain closed. Cooling and Heating modes are disabled. Morning Warmup The purpose of this state is to raise the temperature of the space efficiently by keeping the outdoor air dampers closed. Control in this state is identical to the Unoccupied Heating state. Heating is on. Occupied Heating The only difference between Morning Warmup and this state is that any 2-position outdoor air damper is opened and air-side economizers are opened to minimum position for ventilation. After the unit enters this state from Morning Warmup, the outdoor air damper remains fully open and air-side economizers remain open to at least the minimum position until the unit is turned off at the end of the occupied period. The unit may reenter this state from Fan Only later in the occupied period if the space temperature drops sufficiently. Post Heat In this state, the variable inlet vanes for the supply fans are driven shut for two to three minutes before normal control is resumed. The Heat/VAV output remains in the "Open" position to keep the VAV boxes open while the variable inlet vanes close. The purpose of this state is to prevent high duct pressures when VAV boxes that are wide open in heating suddenly close in response to low space temperatures when they are released to normal cooling control. Heating and cooling are disabled. Fan On Heating The purpose of this state is to prevent cold air from being supplied to the space when the space temperature does not indicate the need for heat. Operation in this state may be required when the minimum outside air requirement is large. Modulating Heat and Staged Electric Heat are controlled to maintain the Supply Air Temperature at the Fan On Heating Setpoint for units with Zone Control and at the current Cooling Supply Setpoint for units with Supply Air Temperature Control. Microtech Self-Contained AC System Open Protocol 12

13 Fan On Unit Transitions The unit operates in this state when an acceptable space temperature can be maintained without either heating or cooling. Operation in this state is similar to Recirculation except that minimum fresh air ventilation is maintained. Any 2-position outdoor air damper is opened and the airside economizer is opened to the minimum position. Heating and cooling are disabled. Economizer In this state, the required cooling can be provided by supplying unconditioned outside air to the space when an air-side economizer is installed. If a waterside economizer is installed, the required cooling can be maintained by modulating the waterside economizer valve. In both cases, the economizer is controlled to maintain the Supply Air Temperature Setpoint using the Step and Wait function. However, an air-side economizer will not be controlled below the edited minimum damper position. Mechanical Cooling When the unit is in this state, compressors or a chilled water coil are controlled to maintain the desired conditions. Heating is disabled. Air-side economizer dampers are controlled either to the fully open position if the outside air is suitable for cooling or to the minimum position if it is not. The waterside economizer valve is fully opened if the entering water temperature is suitable for cooling; otherwise it is fully closed. Unoccupied Operation The unit has the capability of operating during unoccupied periods to keep the space temperature within unoccupied setpoints. Since ventilation is not required, the outdoor dampers normally remain closed in order to heat or cool the space more rapidly and efficiently. If outside air can be used to provide cooling, the outdoor dampers may be opened during the Unoccupied Cooling state. Both SAT and Zone Control units change from state to state as described in the following chart. Units with 100% Outdoor Air go directly from Startup Initialize to either Fan On or Heating since the Recirculate and NSB/Morning Warmup states do not exist in these types of units. SAT and Zone Control States Off Economizer Startup Initialize Mech Cooling Fan On Recirculate Nsb / Mwup Post Heat Fan On Heating Heating 13 Microtech Self-Contained AC System Open Protocol

14 Self-Contained Unit Variables Read Only Memory Locations Variable Name Address Range Units Air Velocity $ Feet per minute Airflow Status $045C 0-1 No units 0 = No Flow 1 = Flow Alarm, Current $ No units 0 = None 1 = Filter Dirty 2 = Airflow Warning 3 = Economizer Stuck 4 = No Water Flow 5 = Heat Fail 6 = Low Airflow 7 = Mixed Air Temp Sensor Problem 8 = Outdoor Air Temp Sensor Problem 9 = Return Air Temp Sensor Problem 10 = Zone Temp Sensor Problem 11 = Supply Air Temp Sensor Problem 12 = Entering Water Temp Sensor Problem 13 = Compressor #1 Fail 14 = Compressor #2 Fail 15 = Compressor #3 Fail 16 = Compressor #4 Fail 17 = Compressor #5 Fail 18 = Compressor #6 Fail 19 = Current Sensor Problem 20 = Velocity Sensor Problem 21 = Low Speed Fan Problem 22 = High Speed Fan Problem 23 = Freeze Problem 24 = Vanes Stuck 25 = Fan Fail 26 = Low Supply Air Temperature 27 = High Supply Air Temperature 28 = High Return Air Temperature 29 = Supply Air Temp Sensor Fault 30 = Return Air Temp Sensor Fault 31 = Duct High Limit 32 = Smoke Shutdown 33 = Freeze Shutdown 34 = High Temperature Rise 35 = Outdoor Air Temp Sensor Fault 36 = Mixed Air Temp Sensor Fault 37 = Zone Temp Sensor Fault 38 = Outdoor Air Damper Stuck Alarm, Previous 0 = None 1 = Filter Dirty 2 = Airflow Warning 3 = Economizer Stuck 4 = No Water Flow 5 = Heat Fail 6 = Low Airflow 7 = Mixed Air Temp Sensor Problem 8 = Outdoor Air Temp Sensor Problem 9 = Return Air Temp Sensor Problem 10 = Zone Temp Sensor Problem 11 = Supply Air Temp Sensor Problem $ ; No units Microtech Self-Contained AC System Open Protocol 14

15 Variable Name Address Range Units 12 = Entering Water Temp Sensor Problem 19 = Current Sensor Problem 20 = Velocity Sensor Problem 21 = Low Speed Fan Problem 22 = High Speed Fan Problem 23 = Freeze Problem 24 = Vanes Stuck 25 = Fan Fail 26 = Low Supply Air Temperature 27 = High Supply Air Temperature 28 = High Return Air Temperature 29 = Supply Air Temp Sensor Fault 30 = Return Air Temp Sensor Fault 31 = Duct High Limit 32 = Smoke Shutdown 33 = Freeze Shutdown 34 = High Temperature Rise 35 = Outdoor Air Temp Sensor Fault 36 = Mixed Air Temp Sensor Fault 37 = Zone Temp Sensor Fault 38 = Outdoor Air Damper Stuck 39 = High Pressure, Compressor #1 40 = Low Pressure, Compressor #1 41 = Frost, Compressor #1 42 = Motor Protect, Compressor #1 43 = Water Regulating Valve Fail, Compressor #1 44 = High Pressure, Compressor #2 45 = Low Pressure, Compressor #2 46 = Frost, Compressor #2 47 = Motor Protect, Compressor #2 48 = High Pressure, Compressor #3 49 = Low Pressure, Compressor #3 50 = Frost, Compressor #3 51 = Motor Protect, Compressor #3 52 = High Pressure, Compressor #4 53 = Low Pressure, Compressor #4 54 = Frost, Compressor #4 55 = Motor Protect, Compressor #4 56 = High Pressure, Compressor #5 57 = Low Pressure, Compressor #5 58 = Frost, Compressor #5 59 = Motor Protect, Compressor #5 60 = High Pressure, Compressor #6 61 = Low Pressure, Compressor #6 62 = Frost, Compressor #6 63 = Motor Protect, Compressor #6 Building Static Pressure $ inches water Compressor #1 Alarm $081C 0-5 No units 0 = None 1 = High Pressure 2 = Low Pressure 3 = Frost 4 = Motor Protect 5 = Water Regulating Valve Fail Compressor #1 Operating Hours $08AF - $08B0 0-50,000 Hours Compressor #2 Alarm $081D 0-5 No units Same as Comp#1Alarm Compressor #2 Operating Hours $08B2 - $08B3 0-50,000 Hours Compressor #3 Alarm Same as Comp#1Alarm $081E 0-5 No units 15 Microtech Self-Contained AC System Open Protocol

16 Variable Name Address Range Units Compressor #3 Operating Hours $08B5 - $08B6 0-50,000 Hours Compressor #4 Alarm Same as Comp#1Alarm $081F 0-5 No units Compressor #4 Operating Hours $08B8 - $08B9 0-50,000 Hours Compressor #5 Alarm Same as Comp#1Alarm $ No units Compressor #5 Operating Hours $08BB - $08BC 0-50,000 Hours Compressor #6 Alarm Same as Comp#1Alarm $ No units Compressor #6 Operating Hours $08BE - $08BF 0-50,000 Hours Control Temperature $ F Cool Stage $043F 0-8 No units Cooling Control Status $044A 0-16 No units 0 = Off: Unoccupied 1 = Off: No Water Flow 2 = Off: Temperature 3 = Network Disable (Bridge) 4 = Network Disable 5 = Switch Disable 6 = Manual Disable 7 = Off: Alarm 8 = Off: Temp and Comp #1 Fail 9 = No Cooling Available 10 = Compressors Only (No Econo) 11 = Compressors Only (Hi Enthalpy) 12 = Economizer Only: Purge 13 = Economizer Only: Low Temp 14 = Economizer Only: No Water Flow 15 = Economizer Only: Low Airflow 16 = All Cooling Enabled Dew Point Temperature $042F F Duct Static Pressure #1 $ inches water Duct Static Pressure #2 $ inches water Economizer Enable $045A 0-1 No units 0 = Enable 1 = Disable Economizer Operating Hours $08C4 - $08C5 0-50,000 Hours Economizer Position $042E Percent Entering Water Temperature $042C 0-255; 252 = short F 253 = N/A 254 = open Fan - High Speed Operating $08AC - $08AD 0-50,000 Hours Hours Fan - Low Speed Operating $08A9 - $08AA 0-50,000 Hours Hours Fan Operation $ No units 0 = Off 1 = On Fan Speed $ Percent Heat Stage $043E 0-8 No units Microtech Self-Contained AC System Open Protocol 16

17 Variable Name Address Range Units Heating Control Status $044C 0-7 No units 0 = Off: OAT Lockout 1 = Off: Unoccupied 2 = Network Disable (Bridge) 3 = Network Disable 4 = Switch Disable 5 = Manual Disable 6 = Off: Alarm 7 = Heating Enabled Heating Operating Hours $08C1 - $08C2 0-50,000 Hours Leaving Water Temperature $042D 0-255; 252 = short F 253 = N/A 254 = open Mixed Air Temperature $042B 0-255; 252 = short F 253 = N/A 254 = open Motor Amps $ RLA Motor Speed $04BB 0-1 No units 0 = Low Speed 1 = High Speed Network Communications Status $ No units 0 = No Comm 1 = Comm OK Outdoor Air Damper Status $045F 0-1 No units 0 = Damper Closed 1 = Damper Open Outdoor Air Temperature $ Subtract 100 from value to get OAT in F Override Hours $08C7 - $08C8 0-50,000 Hours Refrigerant Pressure $ psi Relative Humidity $ %RH Return Air Temperature $ ; 252 = short F 253 = N/A 254 = open Space Temperature $042A 0-255; 252 = short F 253 = N/A 254 = open Supply Air Temperature $ ; 252 = short F 253 = N/A 254 = open Supply Fan Status $045E 0-2 No units 0 = Off 1 = On (single motor) 1 = Low Speed (dual motor) 2 = High Speed (dual motor) Unit Enabled Status 0 = Not Enabled 1 = Enabled $ No units 17 Microtech Self-Contained AC System Open Protocol

18 Variable Name Address Range Units Unit Status $043D 0-35 No units 0 = Program Inactive 1 = Off, Unoccupied 2 = Off, Fan Switch 3 = Off, Network 4 = Off, Manual 5= Off, Service 6 = Off, Alarm 7 = Calibrate 8 = Start Requested 9 = Startup Initialize 10 = Recirculation 11 = Fan On 12 = Heating 13 = Morning Warmup 14 = Fan On with Heating 15 = Post Heat 16 = Economizer 17 = Mechanical Cooling 18 = Heating Stage xx 19 = Morning Warmup Stage xx 20 = Fan On with Heating Stage xx 23 = Mechanical Cooling Stage xx 24 = Unoccupied Heating 25 = Unoccupied Heating Stage xx 26 = Unoccupied Cooling 27 = Unoccupied Cooling Stage xx 28 = Unoccupied Economizer 29 = Dehumidify: Fan On 30 = Dehumidify: Heating 31 = Dehumidify: Morning Warmup 32 = Dehumidify: Fan On with Heat 33 = Dehumidify: Post Heat 34 = Dehumidify: Economizer 35 = Dehumidify: Cooling Variable Inlet Vane Position $ Percent Water Flow Required $ No units 0 = No Flow Required 1 = Flow Required Water Flow $045B 0-1 No units 0 = No Flow 1 = Flow Water Pump Start/Stop 0 = Off 1 = On $ No units Air Velocity $0434 The air velocity in feet per minute (fpm). The linear relationship is as follows: Velocity (fpm) = ($ )*419/51 Which yields the following minimum and maximum air velocities: 0 = -419 fpm 255 = 1676 fpm The resolution is approximately 8.2 fpm. This location is only valid if the unit is configured for dual motor. Microtech Self-Contained AC System Open Protocol 18

19 Airflow Status $045C Tells you whether the unit senses the presence of airflow. For CAV units, the airflow status is based completely on the state of the airflow switch. For VAV units, the airflow status is based on the state of the airflow switch and the presence of duct static pressure: If the airflow switch is closed or the duct static pressure is greater than one-half of the setpoint, airflow status will be indicated. Alarm, Current $0801 The current unit alarm. If multiple alarms exist at the same time, the most serious alarm is given. See the operation manual for more information about alarms. Alarm, Previous $1301 The most recent previous unit alarm. The labels are the same as the Alarm, Current with two exceptions: (1) the specific compressor alarms are included at the end of the list and (2) the generic compressor alarms (labels 13 18) do not apply. See the operation manual for more information about alarms. Building Static Pressure $0435 The building static pressure. The data is valid only when the unit is configured for building static pressure control. The linear relationship is as follows: Building Static Pressure (inches water) = ($ )/500 Which yields the following minimum and maximum pressures: 0 = IWC 255 = IWC Compressor #1 Alarm $081C The current alarm in compressor #1. Compressor #1 Operating Hours $08AF-$08B0 The total number of hours compressor #1 has run. The value rolls over to 0 after 50,000 hours. Compressor #1 Hours = (256 * high byte) + low byte Compressor #2 Alarm $081D The current alarm in compressor #2. Compressor #2 Operating Hours $08B2-$08B3 The total number of hours compressor #2 has run. The value rolls over to 0 after 50,000 hours. Compressor #2 Hours = (256 * high byte) + low byte Compressor #3 Alarm $081E The current alarm in compressor #3. Compressor #3 Operating Hours $08B5-$08B6 The total number of hours compressor #3 has run. The value rolls over to 0 after 50,000 hours. Compressor #3 Hours = (256 * high byte) + low byte Compressor #4 Alarm $081F The current alarm in compressor #4. Compressor #4 Operating Hours $08B8-$08B9 The total number of hours compressor #4 has run. The value rolls over to 0 after 50,000 hours. Compressor #4 Hours = (256 * high byte) + low byte Compressor #5 Alarm $0820 The current alarm in compressor #5. Compressor #5 Operating Hours $08BB-$08BC The total number of hours compressor #5 has run. The value rolls over to 0 after 50,000 hours. Compressor #5 Hours = (256 * high byte) + low byte 19 Microtech Self-Contained AC System Open Protocol

20 Compressor #6 Alarm $0821 The current alarm in compressor #6. Compressor #6 Operating Hours $08BE-$08BF The total number of hours compressor #6 has run. The value rolls over to 0 after 50,000 hours. Compressor #6 Hours = (256 * high byte) + low byte Control Temperature $0432 The temperature that controls the heat/cool changeover. It can be configured to be sourced from the return air sensor, space sensor, outdoor air sensor, mixed air sensor, or a network signal with the Control Temp Source. The resolution is 1 F. Cool Stage $043F The current cooling stage. Cooling Control Status $044A The current state of the cooling equipment within the unit. See the operation manual for more information. Dew Point Temperature $042F The dew point temperature in the space or return air, depending on how the Dew Point Temp Sensor Type. The resolution is 1 F. Duct Static Pressure #1 $0435 The duct static pressure at sensor #1. The data is valid only when the unit is configured for duct static pressure control. The resolution is 0.02 inches of water. Slope = = 0.00 IWC Intercept = = 5.10 IWC Microtech Self-Contained AC System Open Protocol 20

21 Duct Static Pressure #2 $0434 The duct static pressure at sensor #2. The data is valid only when the unit is configured for duct static pressure control and the sensor is present. The resolution is 0.02 inches of water. Slope = = 0.00 IWC Intercept = = 5.10 IWC Economizer Enable $045A The state of the airside or waterside economizer control function. When the economizer is enabled, cool outside air or entering water can be used for free cooling. Economizer Operating Hours $08C4-$08C5 The number of hours the economizer has been enabled. The value rolls over to 0 after 50,000 hours. Economizer Hours = (256 * high byte) + low byte Economizer Position $042E The economizer damper position (percent open to outdoor air). The resolution is 1%. Entering Water Temperature $042C The temperature of the water entering the condenser and waterside economizer (if present). The resolution is 1 F. Note that values 252 through 254 are special and indicate sensor status. Fan - High Speed Operating Hours $08AC-$08AD The number of hours the high-speed fan has run. Valid only for dual-motor units. The value rolls over to 0 after 50,000 hours. Fan -High Speed Hours = (256 * high byte) + low byte Fan - Low Speed Operating Hours $08A9-$08AA The number of hours the fan has run. For dual-motor units, this object holds the number of hours the low-speed fan has run. The value rolls over to 0 after 50,000 hours. Fan -Low Speed Hours = (256 * high byte) + low byte Fan Operation $0462 The state of the fan operation output on the controller. Note that this output is not the same as the fan start/stop output. The fan operation output is energized throughout the Start-up Initialization state in which the supply fan is off and the unit prepares itself for actual startup. The fan operation output remains energized whenever the supply fan is on, and it remains energized for approximately 30 seconds after the fan stops. The fan operation output and this object are intended to be used to activate VAV boxes or other external hardware just before the supply fan starts, giving them time to prepare. It also provides a delay after the fan shuts down to let the ductwork de-pressurize before disabling the VAV boxes or other external hardware. Fan Speed $0436 The position (percent open) of the speed of the supply fan. The value is generated by an actual feedback signal. The resolution is 1%. The data is valid only when the unit is equipped with inverters. Heat Stage $043E The current heating stage. Heating Control Status $044C The current state of the heating equipment within the unit. See the operation manual for more information. Heating Operating Hours $08C1-$08C2 The number of hours the heating equipment has been enabled. The value rolls over to 0 after 50,000 hours 21 Microtech Self-Contained AC System Open Protocol

22 Heating Hours = (256 * high byte) + low byte Leaving Water Temperature $042D The temperature of the water leaving the condenser. The resolution is 1 F. Note that values 252 through 254 are special and indicate sensor status. Mixed Air Temperature $042B The mixed air temperature. The resolution is 1 F. Note that values 252 through 254 are special and indicate sensor status. Motor Amps $ = 0 RLA; 255 = Max RLA The Max RLA is defined in Menu 17 on the keypad. The current draw of the low-speed fan motor. The resolution is 1 A. The data is valid only when the unit is equipped with dual motors.. Motor Speed Tells you which motor speed is currently selected. This location is valid only for units with dual motors. Network Communications Status $0470 The status of the BAS-to-unit network communications watchdog. If a non-zero value has been written to the Network Signal object ($044E) within the last five minutes, this object will indicate Comm OK. Outdoor Air Damper Status $045F The status of the outdoor air damper. The Damper Open state indicates that the damper is operational; i.e., it may be at minimum position, fully open, or anything in between. The Damper Closed state indicates that the controller is driving the damper fully closed. Outdoor Air Temperature $0429 Subtract 100 from this location to obtain the outdoor air temperature, in degrees F. The resolution is 1 F. Note that values 152 through 154 are special and indicate sensor status. The data is valid only when an outdoor air temperature sensor is present. Override Hours $08C7-$08C8 The number of hours the schedule override timer has been set. This timer can be set either manually or via a tenant override button. The value rolls over to 0 after 50,000 hours. Override Hours = = (256 * high byte) + low byte Refrigerant Pressure $0431 The pressure of the refrigerant in the liquid line of circuit #1. The resolution is 1 psi. The data is valid only when the unit is equipped with a pressure sensor and configured for head pressure control. Relative Humidity $0431 The relative humidity of the air in the space. The resolution is 1%. The data is valid only when the unit is equipped with a humidity sensor and configured for dehumidification control. Return Air Temperature $0428 The return air temperature. The resolution is 1 F. Note that values 252 through 254 are special and indicate sensor status. The data is valid only when a return air temperature sensor is present. Space Temperature $042A The space temperature. The resolution is 1 F. Note that values 252 through 254 are special and indicate sensor status. The data is valid only when a space temperature sensor is present. Supply Air Temperature $0427 The supply air temperature. The resolution is 1 F. Note that values 252 through 254 are special and indicate sensor status. Supply Fan Status $045E The status of the supply fan. The value 2 is valid only for units with dual motors. Microtech Self-Contained AC System Open Protocol 22

23 Unit Enabled Status $0488 Indicates the presence of a condition that would enable the unit to run. This object will indicate Enabled whenever one or more of the following conditions is present: A local daily or holiday schedule in occupied A local control mode setting of Occupied A network control mode ($044F) setting of Occupied (the local control mode must be set to Auto) A contact closure at the system on/off input (hardware DI-8) An active tenant override or operator override time period An active optimal start period A call for unoccupied heating or cooling If this object indicates Enabled, it means that the unit will run if some other disabling condition is not overriding it (e.g., a fault alarm). Thus this object might indicate enabled even though the unit is actually disabled. If this object indicates Not Enabled, the unit will not operate. Unit Status $043D The overall state of the unit. See the operation manual for more information. Variable Inlet Vane Position $0436 The position (percent open) of the supply fan variable inlet vanes. The value is generated by an actual feedback signal. The resolution is 1%. The data is valid only when the unit is equipped with inlet vanes. Water Flow Required $0445 Indicates whether the unit requires water flow for either waterside economizer operation or compressor operation. When the BAS has direct control over a pump start/stop output, this object can be used to trigger the pump control algorithm. Water Flow $045B The water flow status. If a flow switch is connected to the MicroTech controller and the controller is configured for a local flow switch, this location will indicate the status of the local flow switch. If the controller is configured for no local flow switch, this location will indicate the state of the flow status signal received over the network through the Network Water Flow Signal ($0444). Water Pump Start/Stop $0461 Indicates whether the unit has started a pump that is directly controlled by the MicroTech unit controller s outputs. The Digital Outputs section of bulletin IM 608 discusses the Pump Start field wiring output that can be used to operate a pump whenever the unit is on and heating is off. This location provides the status of the Pump Start field wiring output. Note: This object could also be used to trigger pump operation in a BAS that has direct control over a pump start/stop output, but the Water Flow Required ($0445) would be a better choice because it will not allow the pump to operate during the Fan Only state in which cooling (and thus water) is not required. 23 Microtech Self-Contained AC System Open Protocol

24 Read/Write Memory Locations Variable Name Address Range (Default) Units Building Static Pressure Setpoint $ (150) Subtract 125 and divide by 500 = inches water Clear Alarm $04CE 0-1 (0) 0 = No 1 = Yes Clear Alarm Buffer $048A 0-1 (0) 0 = No 1 = Yes Control Mode $044F 0-5 (1) No units 0 = Off 1 = Auto 2 = Occupied 3 = Occupied, Cooling Only 4 = Occupied, Heating Only 5 = Occupied, Fan Only Control Temperature Source $ (0) No units Cooling Control Deadband $088D 1-10 (1) F Cooling Control Setpoint $ (72) F Cooling Supply Deadband $ (1) F Cooling Supply Setpoint $090E 4-100(55) F Dew Point Deadband $094E 0-10 (2) F Dew Point Sensor Type $ (0) No units 0 = Return 1 = Space Dew Point Setpoint $094D 0-99 (50) F Duct Static Pressure Setpoint $ (50) Multiply by 0.02 = inches water Duct Static/Building Static Pressure Deadband Economizer (Air) Changeover Differential Economizer (Air) Changeover Temperature Setpoint Economizer (Air) Method 0 = OAT Dry Bulb 1 = Enthalpy Switch Economizer (Water) Changeover Temperature Offset $089B 0-50 (4) Multiply by 0.02 = inches water $ (3) F $ (175) $083B 0-1 (1) No units $091A 0-10 (3) F Fan On Heating Setpoint $ (60) F Head Pressure Deadband $08E (10) psi Head Pressure Setpoint $093A (160) psi Heating Control Deadband $ (1) F Heating Control Setpoint $ (68) F Heating Supply Deadband $ (1) F Heating Supply Setpoint $ (100) F Subtract 100 from value to get OAT in F Microtech Self-Contained AC System Open Protocol 24

25 Variable Name Address Range (Default) Humidity Control Type $ (0) No units 0 = None 1 = Relative Humidity Control 2 = Dew Point Control Humidity Deadband $094C 0-10 (2) %RH Humidity Setpoint $094B 0-99 (50) %RH Low Entering Water Compressor Lockout Differential $092C 1-10 (3) F Low Entering Water Compressor Lockout Setpoint $092B 0-100(55) F Min Vane Position/Fan Speed for $ (60) Percent Building Static Pressure Control Minimum Outdoor Air Damper Position $ (10) Percent Minimum Supply Air Temperature $ (0) No units Control 0 = No 1 = Yes Unoccupied Cooling Space Differential $ (3) F Unoccupied Cooling Space Setpoint $ (85) F Unoccupied Heating Space Differential $ (3) F Unoccupied Heating Space Setpoint $ (55) F Water Flow Signal 0 = No Flow 1 = Flow $ (1) No units Units Building Static Pressure Setpoint $0923 The building static pressure setpoint. The resolution is inches of water. This location is valid only when the CAV unit is equipped and configured for building static pressure control. The deadband associated with this setpoint is available only at the unit s keypad/display. The linear relationship is as follows: Building Static Pressure Setpoint (inches water) = ($ )/500 Which yields the following minimum and maximum pressures: 0 = IWC 255 = IWC Clear Alarm $04CE Clears the current active alarm. The location s value automatically changes to zero when the alarm is cleared. Note that some alarms are self-clearing. This location would need to be used only for manual-clear alarms. (If a self-clearing alarm is cleared with this object, it will recur immediately since the alarm condition is still present. No harm will occur.) Note: Never command this variable without investigating and correcting the cause of the alarm. Clear Alarm Buffer $048A To clear all previous alarms, set this memory location to $01. After clearing the alarms, the program sets this memory location back to zero. 25 Microtech Self-Contained AC System Open Protocol

26 Control Mode $044F The network control mode for the unit. This object should not be confused with the local Control Mode parameter that is available on the unit s keypad display. This control mode location is effective only when the local control mode parameter is set to Auto. The local control mode thus acts like a local hand-off-auto switch, allowing a remote signal to control the unit only when the local mode is set to auto. The following discussion of this object assumes that the local control mode is set to Auto. If a 0 (Off) is written to this object, the unit will be disabled. It will not run for any reason. If a 1 (Auto) is written to this object, the unit will be enabled, but it will not necessarily run. In fact, this is the typical way of turning the unit off via network command. Unless another unit control function is calling for the unit to be on, the unit is placed in the unoccupied mode and turned off. Other unit control functions that could turn the unit on are as follows: Unoccupied heating or cooling conditions (night setback or night setup) Tenant override or operator override timer set Digital input for unit start/stop set for occupied operation (typically not used in a BAS application) Local scheduling (typically not used in a BAS application) The first two means of turning on the unit may be desired even in a BAS application, and thus it may be preferable to use a 1 (Auto) to shut down the unit rather than a 0 (Off). If a 2 (Occupied) is written to this object, the unit will start and run in occupied mode unless it is disabled for some other reason such as a fault. If a 3 (Occupied, Cooling Only) is written to this object, the unit will start and run in occupied mode unless it is disabled for some other reason such as a fault. Heating will be disabled. If a 4 (Occupied, Heating Only) is written to this object, the unit will start and run in occupied mode unless it is disabled for some other reason such as a fault. All cooling (including economizer) will be disabled. If a 5 (Occupied, Fan Only) is written to this object, the unit will start and run in occupied mode unless it is disabled for some other reason such as a fault. All heating and cooling (including economizer) will be disabled. Note: This object s value is stored in volatile memory, so after a power reset the desired value must be rewritten to the MicroTech controller. Control Temperature Source $0926 The source of the Control Temperature. (The heating/cooling state in which the unit operates during the occupied period is based primarily on the Control Temperature.) If Network (2) is selected, the Control Temperature can be directly set by writing to the Network Control Temperature ($0443). But note that when Network is selected, a communication watchdog signal must also be written to the Network Signal($044E) at least once every three minutes. Otherwise, the Network value (2) will automatically revert to Return Air (0). If communications are subsequently restored, the Network value will automatically be restored by the MicroTech controller. Cooling Control Deadband $088D The deadband for the Cooling Control Setpoint. The resolution is 1 F. Cooling Control Setpoint $0907 The SCU uses the Cooling Control Setpoint to determine if it should go into the cooling mode. The SCU will go into the cooling mode if the Cooling Control Temperature is greater than the Cooling Control Setpoint plus the Cooling Control Deadband. The rooftop will leave the cooling mode when the Cooling Control Temperature is less than the Cooling Control Setpoint minus the Cooling Control Deadband. This setpoint is used only during occupied periods for zone control applications. The resolution is 1 F. Cooling Supply Deadband $0878 The deadband for the supply air cooling setpoint. The resolution is 1 F. Microtech Self-Contained AC System Open Protocol 26

27 Cooling Supply Setpoint $090E The supply air cooling setpoint. This setpoint can be written to only when the unit is configured for supply air temperature control and no cooling reset. (The reset type configuration parameter can be checked or adjusted at the unit s keypad/display. The range of this location is controlled by the min and max spt. The defaults are a min spt of 55F and a max spt of 65F and are only adjustable at the keypad). For zone control or cooling reset control applications, the MicroTech controller will automatically adjust the supply air cooling setpoint and this location can be used to read its current value. The resolution is 1 F. Dew Point Deadband $094E The deadband for the dew point setpoint. This object is used only when the Humidity Control Type ($0947) is set to Dew Point. The resolution is 1 F. Dew Point Sensor Type $0949 A configuration parameter that defines the source of the temperature to be used to calculate the dew point. The MicroTech controller calculates the dew point using the relative humidity and either the space or return air temperature. Dew Point Setpoint $094D The dew point setpoint for the space. When dehumidification control is enabled, the unit will remove moisture from the air as required to maintain this setpoint. This object is used only when the Humidity Control Type ($0947) is set to Dew Point. The resolution is 1 F. Duct Static Pressure Setpoint $0917 The duct static pressure setpoint. This location is used only when the unit is equipped and configured for duct static pressure control. The resolution is 0.02 inches of water. Slope = = 0.00 IWC Intercept = = 5.10 IWC Note that the values written to this location will be limited to a maximum value that is defined by the Maximum Duct Static Pressure Setpoint. This setpoint s default value is 2.00 inches, and it can be adjusted at the unit s keypad/display. Duct Static/Building Static Pressure Deadband $089B The deadband for the duct static pressure setpoint. This object is used only when the unit is equipped and configured for duct static pressure control. The resolution is 0.02 inches of water. Slope = = 0.00 IWC Intercept = = 5.10 IWC Economizer (Air) Changeover Differential $0932 The differential for the economizer changeover temperature setpoint. This object is valid only for units equipped with airside economizers. The resolution is 1 F. Economizer (Air) Changeover Temperature Setpoint $0931 The economizer changeover temperature for applications in which the outdoor air dry bulb temperature is used to determine the suitability of the outdoor air for free cooling. This object is valid only for units equipped with airside economizers. The resolution is 1 F. The outdoor air is considered suitable for free cooling if the outdoor air temperature is less than or equal to this location s value. The outdoor air is considered unsuitable for free cooling if the outdoor air temperature is greater than the sum of this location s value and the Economizer (Air) Changeover Temperature Differential ($0931) location s value. Within the differential range, the airside economizer could be either enabled or disabled. 27 Microtech Self-Contained AC System Open Protocol

28 Economizer (Air) Method $083B A configuration parameter that defines how the airside economizer determines the suitability of the outdoor air for free cooling. If OAT Dry Bulb (0) is selected, the outdoor air temperature will be compared with a setpoint (see Economizer (Air) Changeover Temperature Setpoint ($0931). If Enthalpy Switch (1) is selected, the controller will use a digital input signal from an optional external enthalpy sensor to make the decision. Economizer (Water) Changeover Temperature Offset $091A An offset that defines the waterside economizer changeover temperature setpoint. The MicroTech controller calculates the actual changeover setpoint by subtracting this location s value from the current mixed air temperature ($042B). This location is valid only for units equipped with waterside economizers. The resolution is 1 F. When the entering water temperature ($042C) falls below the calculated changeover setpoint, the economizer is enabled. When the entering water temperature rises above the calculated changeover setpoint, the economizer is disabled. When the entering water temperature is right at the calculated changeover setpoint, the waterside economizer could be either enabled or disabled (thus there is a fixed 2 F differential). Fan On Heating Setpoint $0939 The supply air setpoint used when a zone control unit is in the Fan On-Heating state. This setpoint is used only in CAV, zone control units, and then only if minimum supply air temperature control is enabled (see Minimum Supply Air Temperature Control ($0919)) or dehumidification is active. The Fan On-Heating state acts to maintain a minimum supply air temperature, and thus this setpoint can be thought of as a discharge air low limit setpoint. The resolution is 1 F.. Head Pressure Deadband $08E1 The deadband for the head pressure setpoint. This object is used only when the unit is equipped and configured for head pressure control. The resolution is 1 psi. Head Pressure Setpoint $093A The head pressure setpoint. This object is used only when the unit is equipped and configured for head pressure control. The resolution is 1 psi. When compressor #1 is on, head pressure control will modulate the flow of the entering condenser water to maintain the condenser pressure ($0431) at this setpoint. Heating Control Deadband $0894 The deadband for the Heating Control Setpoint. The resolution is 1 F. Heating Control Setpoint $0905 The SCU uses the Heating Control Setpoint to determine if it should go into the heating mode. The rooftop unit will go into the heating mode if the Heating Control Temperature is less than the Heating Control Setpoint minus the Heating Control Deadband. The rooftop will leave the heating mode when the Heating Control Temperature is greater than the Heating Control Setpoint plus the Heating Control Deadband. This setpoint is used only during occupied periods. The resolution is 1 F. Note that the MicroTech controller will automatically limit this setpoint if its value is too close to the space cooling setpoint. (It enforces a minimum 1 F separation between the cooling and heating deadband ranges.) This limiting action will always affect the space heating setpoint regardless of whether the space heating setpoint, the space cooling setpoint, or either deadband is adjusted. Heating Supply Deadband $0871 The deadband for the supply air heating setpoint. The resolution is 1 F.. Heating Supply Setpoint $0914 The supply air heating setpoint. This setpoint can be written to only when the unit is configured for supply air temperature control and no heating reset. (The reset type configuration parameter can be checked or adjusted at the unit s keypad/display.) For zone control or heating reset control applications, the MicroTech controller will automatically adjust the supply air heating setpoint and this object can be used to read its current value. The resolution is 1 F. Microtech Self-Contained AC System Open Protocol 28

29 Humidity Control Type $0947 A configuration parameter that defines whether dehumidification control is enabled or disabled. If dehumidification is enabled, it can be configured to control to either a relative humidity setpoint ($0948) or a dew point setpoint ($094D). Humidity Deadband $094C The deadband for the humidity setpoint. This object is used only when the Humidity Control Type ($0947) is set to Relative Humidity. The resolution is 1% RH Humidity Setpoint $094B The relative humidity setpoint for the space. When dehumidification control is enabled, the unit will remove moisture from the air as required to maintain this setpoint. This object is used only when the Humidity Control Type ($0947) is set to Relative Humidity. The resolution is 1% RH. Low Entering Water Compressor Lockout Differential $092C The differential for the low entering water compressor lockout setpoint. The resolution is 1 F. Low Entering Water Compressor Lockout Setpoint $092B The low entering water compressor lockout setpoint. The resolution is 1 F. Mechanical cooling will be disabled when the entering water temperature is less than this location s value. Mechanical cooling will be enabled when the entering water temperature is greater than the sum of this object s value and the Low Entering Water Compressor Lockout Differential ($092C). Within the differential range, mechanical cooling could be either enabled or disabled. Min Vane Position/Fan Speed for Building Static Pressure Control $0951 The minimum vane position or fan speed setpoint for building static pressure control. This location is used only when the unit is equipped and configured for building static pressure control. The resolution is 1%. Minimum Outdoor Air Damper Position $0934 The minimum position for the outdoor air damper during occupied periods. The resolution is 1%. Minimum Supply Air Temperature Control $0919 A configuration parameter that enables or disables minimum supply air temperature control. When minimum supply air temperature control is enabled, the unit will operate heating equipment as required to maintain a minimum supply air temperature. The unit status ($043D) will be Fan On with Heating when this type of low-limit control is active. Unoccupied Cooling Space Differential $0904 The differential for the unoccupied space cooling (night setup) setpoint. The resolution is 1 F. Unoccupied Cooling Space Setpoint $0903 The unoccupied space cooling (night setup) setpoint. This setpoint is used only during unoccupied periods and only when a space temperature sensor is connected and configured. The resolution is 1 F. Unoccupied cooling will be enabled when the space temperature is greater than or equal to this location s value. Unoccupied cooling will be disabled when the space temperature is less than the sum of this location s value and the Unoccupied Cooling Space Differential ($0904). Within the differential range, unoccupied cooling could be either enabled or disabled. Unoccupied Heating Space Differential $0902 The differential for the unoccupied space heating (night setback) setpoint. The resolution is 1 F Unoccupied Heating Space Setpoint $0901 The unoccupied space heating (night setback) setpoint. This setpoint is used only during unoccupied periods and only when a space temperature sensor is connected and configured. The resolution is 1 F. Unoccupied heating will be enabled when the space temperature is less than or equal to this location s value. Unoccupied heating will be disabled when the space temperature is greater than the sum of this location s value and the Unoccupied Heating Space Differential ($0902). Within the differential range, unoccupied heating could be either enabled or disabled. 29 Microtech Self-Contained AC System Open Protocol

30 Water Flow Signal $0444 A water flow status signal written to the MicroTech controller via the network. This object might be used if a flow switch is directly connected to a piece of BAS hardware. To recognize this network signal, the MicroTech controller must be configured for no local flow switch. This particular configuration parameter is normally set at the factory, but it can also be set in the field by a trained service technician (it is not available at the keypad/display). Note: This object s value is stored in volatile memory, so after a power reset the desired value must be rewritten to the MicroTech controller. Network Control Features It may be desirable to control a network of units in a uniform fashion to allow for such configurations as common supply ducts. Features that allow for this type of control are Network Supply Vane Position and Network Control Temperature. To use these features a network signal must be sent continuously to memory location $044E. A non-zero value must be written at least once per minute to $044E to maintain $0470 (Network Condition) as "Communicating." If this point reverts to "Not Communicating," the Static Pressure Reset Type (if it is currently "Network") will revert to "None" and the Control Temperature (if it is currently "Network") will change to "Return Air." If network communications are restored, these reset types will change back to their original values. Variable Name Address Range Units Network Control Temperature $ F Network Signal $044E No units Network Supply Vane Position/Speed Setpoint $044D Percent Network Control Temperature $0443 The Control Temperature as written by the BAS. This object is used only when the Control Temperature Source ($0926) is set to Network. The resolution is 1 F. See Control Temperature Source (0926) for more information. Note: This object s value is stored in volatile memory, so after a power reset the desired value must be rewritten to the MicroTech controller. Network Signal $044E A BAS-to-unit network communications watchdog. A non-zero value (1 255) should be written to this object once every few minutes if the BAS is directly setting the Network Control Temperature ($0443) or Network Supply Vane/Speed Setpoint ($044D). If the Network Signal location is not updated for five minutes, the MicroTech controller will assume there has been a loss of network communications and revert to internal setpoints for unit control. The Network Communications Status ($0470) tells you whether the MicroTech controller thinks network communications exist. Note: This object s value is stored in volatile memory, so after a power reset the desired value must be rewritten to the MicroTech controller. Network Supply Vane Position/Speed Setpoint $044D The vane position or fan speed setpoint as written by the BAS. This object is used only when the unit is equipped and configured for duct static pressure control, and then only when the duct static pressure reset type parameter is set to Position. (This parameter is available on the unit s keypad/display.) The resolution is 1%. Microtech Self-Contained AC System Open Protocol 30

31 If Position is selected as the duct static pressure reset type, the vane position/speed setpoint can be directly set by writing to this object. But note that when Position reset is selected, a communication watchdog signal must also be written to the Network Signal ($044E) at least once every three minutes. Otherwise, the Position value will automatically revert to No Reset. If communications are subsequently restored, the Position value will automatically be restored by the MicroTech controller. The purpose of Position reset is to allow a BAS to coordinate the supply fan output of two or more units connected to a common supply duct. In such a situation, the duct static pressure control would be performed by the BAS. The unit controllers would simply maintain their vane positions or fan speeds at whatever value the BAS s pressure control loop gives them. If Position reset were not used in a common duct static pressure control application, vane position or fan speed hunting would occur. Note: This object s value is stored in volatile memory, so after a power reset the desired value must be rewritten to the MicroTech controller. 31 Microtech Self-Contained AC System Open Protocol

32 RMC Open Protocol Overview One or more RMC panels may be included in a network to provide remote keypad display capabilities and group control functions. The RMC panel is capable of providing control functions for up to eight unit controllers. These units may be combined into from one to four groups that are then controlled in a common fashion. The group control features of the RMC panel can be accomplished by a BAS either by manipulating the RMC panel memory locations or by writing to the unit controllers directly. The memory locations needed for group control are listed in the Read and Read/Write tables under the Network Read and Network Read/Write headings. Features of the RMC Panel The following section outlines the control features of the RMC panel available through Open Protocol. Control features of the RMC panel are: Common Duct Static Pressure Control Common Space Temperature Control Timeclock Scheduling Common Duct Static Pressure Control When a group of SAT units feeds a common supply air duct, the position of the variable inlet vanes on the supply fans or the speeds of the variable speed supply fan motors on the units can be controlled together. The RMC unit sends a value of 0 to 100% to each unit in a selected group to indicate the desired position of the vanes or speed of the variable speed motor. This value is calculated using the Step and Change function, a static pressure setpoint entered by the user, and a static pressure value determined by the RMC. The static pressure value is the average, minimum, or maximum of all applicable pressure sensors connected to the rooftop units in the group. When Position is selected as the type of reset for Duct Static Pressure, a unit will control to the selected vane position or speed instead of the normal static pressure control. If communications between the RMC and a unit in a group selected for static pressure control are lost, the unit will operate in the normal manner using the static pressure sensor connected to that unit until network communications are restored. Common Space Temperature Control When a group of units feeds a common area, they can be controlled as a single unit by responding to the same Control Temperature. A common Control Temperature is sent from the RMC to all unit controllers in each group. For each group, the user can select either Space or Return as the common Control Temperature. For each group the user can select the average, minimum or maximum of the selected temperature in each unit as the method for determining the common Control Temperature for the group. The unit will control to the common Control Temperature sent from the RMC whenever the user selects Network as the Control Temperature. If communications between the RMC and a unit with Network selected as the Control Temperature are lost, the unit will revert to normal operation using the Return Air Temperature as the Control Temperature until network communications are restored. Timeclock Scheduling The RMC panel features four eight-day schedules, each of which is like the schedule in the unit controller. The user can select which schedule, if any, should be used for each of the eight units. The selection of units to be controlled by these schedules is unrelated to the groups and group functions. Microtech Self-Contained AC System Open Protocol 32

33 When a schedule is on, each unit selected for control by that schedule is sent a signal that places the unit in the occupied mode unless a higher priority control such as a Fault or Manual Off command prevents it from starting. The unit is turned off when this schedule is off and no other function such as timed override or another schedule calls for the unit to be in the occupied mode. The RMC schedules can be set through the RMC panel keypad but are NOT available through Open Protocol. If scheduling is required though Open Protocol, it should be done by writing directly to the individual unit controller. 33 Microtech Self-Contained AC System Open Protocol

34 RMC Variables Read Only Memory Locations Variable Name Address Range Units Control Temperature Group #1 Group #2 Group #3 Group #4 Schedule Status Schedule #1 Schedule #2 Schedule #3 Schedule #4 Speed/Vane Position Group #1 Group #2 Group #3 Group #4 Static Pressure Group #1 Group #2 Group #3 Group #4 $047E $047F $0480 $0481 $0495 $0496 $0497 $0498 $0486 $0487 $0488 $0489 $0482 $0483 $0484 $ F Percent Inches Water Column Control Temperature $047E-$0481 These values are the result of performing the appropriate calculation (minimum, maximum or average, as selected by Group #x Temperature Calculation) on the group control temperatures (return air or space air, as selected by Group #x Control Temperature). Schedule Status $0495-$0498 These fields reflect the occupied status of the schedules. 0 = Unoccupied, 1 = Occupied Speed/Vane Position $0486-$0489 These fields show the group supply vane positions (percent open), based on the group static pressure values. Static Pressure $0482-$0485 These values are the minimum, maximum or average group static pressures, as selected by the Group #x Pressure Calculations). Read/Write Memory Locations Variable Name Address Range Units Control Temperature Group #1 Group #2 Group #3 Group #4 $0917 $091D $0923 $ = Return 1 = Space Microtech Self-Contained AC System Open Protocol 34

35 Variable Name Address Range Units Temperature Calculation Group #1 Group #2 Group #3 Group #4 Pressure Calculation Group #1 Group #2 Group #3 Group #4 Pressure Setpoint Group #1 Group #2 Group #3 Group #4 Group Number Unit #1 Unit #2 Unit #3 Unit #4 Unit #5 Unit #6 Unit #7 Unit #8 $0918 $091E $0924 $092A $091B $0921 $0927 $092D $091A $0920 $0926 $092C $082D $082E $082F $0830 $0831 $0832 $0833 $ = Min 1 = Max 2 = Average = Min 1 = Max 2 = Average Pressures in 0.02 IWC increments (0 = No Group) Control Temperature Group #1 $0917 Group #2 $091D Group #3 $0923 Group #4 $0929 The Control Temperature Setpoint indicates which temperature value to use as the Control Temperature. If this setpoint is set to $00, the Return Air Temperature is used as the common Control Temperature. If this setpoint is set to $01, the Space Air Temperature is used. Temperature Calculation Group #1 $0918 Group #2 $091E Group #3 $0924 Group #4 $092A The common Control Temperature sent to the units can be calculated to be the minimum, maximum, or average of all the temperatures read. If this setpoint is set to $00, the minimum temperature is used. A $01 will cause the maximum temperature to be used. A $02 will signal the RMC panel to average all the temperatures read and use that value as the common Control Temperature. Pressure Calculation Group #1 $091B Group #2 $0921 Group #3 $0927 Group #4 $092D The common Supply Vane Position sent to the unit controllers can be calculated based on the minimum, maximum, or average of all the static pressure values read. If this setpoint is set to $00, the minimum static pressure value is used in this calculation. A $01 will cause the maximum static pressure value to be used. A $02 will signal the RMC panel to average all the static pressure values read and use that value to compute a common Supply Vane Position. 35 Microtech Self-Contained AC System Open Protocol

36 Pressure Setpoint Group #1 $091A Group #2 $0920 Group #3 $0926 Group #4 $092C This is the desired group Static Pressure Setpoint. The RMC panel will control the units to maintain this duct static pressure by varying the Supply Vane Position as required. Group Number $082D-$0834 This section combines units into groups for common control. Each unit may be assigned to one of four groups. A $00 indicates that the unit is not associated with any group. Microtech Self-Contained AC System Open Protocol 36

37 Interface Development and Testing Required Development Testing Tools In order to develop and test an Open Protocol interface, the following equipment is highly recommended. 1. McQuay International "Open Protocol Data Communications" documents for the SCU. Be sure to check for the most current version (on McQuay Online). 2. McQuay Open Protocol Hardware Simulators (available for purchase). Model 280 RS-232 Communications Cable Pigtail or RS-485 Pigtail 3. Self-Contained Unit Simulator Software (on McQuay Online) 4. Monitor Program Users Manual (available upon request) Setup of Hardware for Testing Communications Cable One setup that is particularly helpful for proving out an Open Protocol interface is shown below. In this arrangement, the Open Protocol interface is operational on Port A and the McQuay Monitor program is operational on Port B. Address "00.00" Level 1 SCU A BAS B (9600 Baud) "Monitor" Software The procedure for setting up this network arrangement is as follows: 1. Install the Self-Contained Unit Open Protocol simulation software on your PC. The Monitor program is a program used to communicate from a PC to McQuay controllers. It is a Windows based program. The program will prompt you through its installation. 2. Set the hex address switches on the Model 250 controller to Hi = F, and Lo = F. (This forces Port A to 1200 baud TTY and Port B to 9600 baud TTY) 3. Sonnect the RS-232 communications cable to Port B on the Model 250 controller. 4. Power the Model 250 controller. 5. Invoke the Monitor program. To invoke the Windows Monitor program, double click on the Windows item created during the install procedure. 6. Establish communications with the controller (Monitor program should connect at 9600 baud). 7. Download the correct unit simulator code to the controller. The download option is found under the Support Menu. The following dialog will appear. 37 Microtech Self-Contained AC System Open Protocol

38 The options for this simulator code are: Controller Normal Software ID Simulation Software ID * designates a wild card; any character in this position is acceptable The simulator is now a Level 1 controller, and the controller address is SCU * 50600S2* RMC RMCEA01* RMCEAS1* At the time of publication, the normal software identification was J for the SCU. Note that the download procedure may prompt you that port configurations are being changed; this is normal. Click <OK> to proceed. Also note that the controller is assumed to have all password memory locations set to F. When the download is completed, restart the controller as prompted by the Monitor program. The Monitor program should prompt "Download completed." Click on <Cancel> to exit the download dialog. Remove power from the controller and set the hex address switches to Hi = 0 and Lo = 1. Apply power to the controller once again and establish communications with the Monitor program. The "Initiate Communication" function is found under the Communication menu The simulator code has Port A set to 9600 baud TTY and Port B set to 9600 baud TTY by default. The BAS communications device should now be able to communicate at 9600 baud on Port A. 1. With both ports communicating, it is possible to read and write memory locations simultaneously via the Monitor program on Port B and BAS communications device on Port A. 2. The Monitor Program provides the means to easily check each memory location and to monitor the results of signals sent to the controller. The single controller software program may be customized by changing parameters on the Factory Setup screen. The unit responds differently to some signals from the BAS communications device depending on the configuration of the unit. Microtech Self-Contained AC System Open Protocol 38