HEAT CALCULATOR MODEL 212 July 1998
CONTENTS 1. Overview 1.1 Model Number Designation 1.2 Conversion Factors 3 5 6 2. Specification 7 3. Operation 3.1 Display Operation 3.1.1 Normal Operation 3.1.2 Charge/Discharge Operation 3.1.3 Peak and Off-Peak Operation 3.2 Checking Set-up Parameters 3.3 Units of Measurement 3.4 Frequency Cut-off 3.5 Offset Functions 3.6 Operating Modes 3.6.1 Heating 3.6.2 Cooling 3.6.3 Heating/Cooling 3.6.4 Charge/Discharge 3.7 Peak and Off-Peak 3.8 Logging 11 13 13 17 18 19 24 25 26 27 27 27 27 28 29 30 4.
5. Set-up Mode 44 6. Input & Output Connections 6.1 Flowmeter Input 6.2 RTD Input 6.3 Power Supply 6.4 Pulse Output 6.5 Alarm Relay Outputs 6.6 4-20mA Output Option 50 50 53 54 55 57 59 7. Installation 7.1 Wall Mounting 7.2 Panel Mount Version 7.3 Removing the Front Panel 7.4 Verification Seal 7.5 Wiring Practices 7.
Overview 3 1. OVERVIEW The Model 212 Heat Calculator is designed to measure the energy consumed in both heating and cooling (air conditioning) systems. The instrument is normally supplied complete with temperature probes and power supply, and will interface to a wide variety of flowmeters, including positive displacement and inferential water meters, magnetic flowmeters with pulse outputs, turbine flowmeters & paddlewheel flowmeters.
4 Overview The Model 212 has a highly accurate built-in real time clock (2ppm typ) to keep track of logging, peak-on/peak-off points, etc. In case of a power failure, the real-time clock is able to keep running for two days with a ± 1 minute accuracy, typically. This instrument conforms to the EMC-Directive of the Council of European Communities 89/336/EEC and the following standards: Generic Emission Standard EN 50081-1 Residential, Commercial & Light Industry Environment.
Overview 1.1 MODEL NUMBER DESIGNATION Model 212 .
6 Overview 1.2 CONVERSION FACTORS 1 kWh 1 MJ 1 m3 1 US gal 1 ft3 1 kBTU 1 Ton x Hour (Refrigeration) 1 therm Note: = = = = = = = = 3.600 MJ 0.27778 kWh 1000 litres 3.785 litres 7.4805 US gal 1.0551 MJ 12,000 BTU 100,000 BTU kBTU are used on the Model 212 display and mean BTU x 1000.
Specification 2. SPECIFICATION General Energy Display units: Maximum Thermal Power: Accuracy Class: Measurement Time: Environmental Class: Ambient Temp Range: Storage Temp Range: kWh, MWh, MJ, GJ, therm, BTU x 1000, tons x hours (refrigeration). 3000 MW. OIML R75 Class 4, EN1434. 0.5 sec time interval. EN1434 Classes A & C. 0°C to 60°C. -20°C to 70°C. Temperature Measurement Type of Sensor: Pt100 to IEC751. Temperature Range: -10°C to 220°C Temperature Difference: 1K to 200K.
8 Specification Flowmeter Input Type: Signal Type: K-factor range: Location: Frequency or Pulse between 0.01Hz to 20kHz. Default low frequency cut-off is 0.25Hz. Pulse, open collector, reed switch, proximity switch or coil. Programmable between 0.001 to 999,999.9 pulse per litre, m3, US gallon or ft3. In either the feed or return lines. Temperature Sensor (RTD) Input Sensor Type: Connection Type: Location: Linearisation: Temperature Range: RTD Cable Length: Pt100 to IEC 751. Four wire.
Specification 9 Construction Enclosure Material: Colour: Protection: Mounting: Dimensions: ABS/Polycarbonate. Light beige. Sealed to IP67 (Nema 4X). Wall mounting or panel mounting. 152mm (6.0") wide x 98mm (3.9") high x 43mm (1.7") deep. Alarm Output (not available if 4-20mA Output Option is installed) Type: Function: Two solid state opto-isolated relays which will sink up to 250mA. 30V dc maximum.
10 Specification RS485 Option Data Transmitted: Baud rate: Parity: Stop bits: Bus Address: Protocol: Volume and energy totals, peak power, temperatures. 300 - 9600 baud. Odd, even or none. One or two stop bits. Programmable for multiple instruments on the same bus. Modbus RTU. Meter-Bus Type: Protocol: Conforms to CEN/TC176 Meter-bus standard. IEC 870-5.
Operation 11 3. OPERATION The Model 212 has three display modes: 1. Display of normal energy and flow information. This information is available by pressing the DISPLAY key. Where appropriate Accumulated Totals can be displayed by pressing the ACCUM TOTAL key. 2. Checking Set-up Parameters. By pressing and holding the DISPLAY key for about 5 seconds, the instrument will enter the parameter set-up routine and allow all set-up parameters to be checked but not changed.
12 Operation Three key switches provide the following functions: Displays the accumulated (non-resettable) totals for Energy, Volume, operating time (elapsed time) and Energy total for log entries. Also changes digits, decimal point or units when entering the set-up parameters. A flashing digit, decimal point or unit will indicate that the parameter can be changed. If the Reset function is enabled during set-up, the RESET key, when held for 5 seconds, will reset all totals and the operating time.
Operation 13 3.1 DISPLAY OPERATION 3.1.1 Normal Operation Data which can be displayed by pressing the DISPLAY key is as follows: (1(5*< ⇓ Default display - Energy measured since the last reset. .:K ⇓ Press ACCUM TOTAL Press DISPLAY $&&80 .:K 7(67 Accumulated Energy Total (non-resettable). Display segments test. Segments are flashing.
14 Operation 32:(5 Energy flow rate .: ⇓ Press DISPLAY )/2: Volume flow rate 0 + ⇓ Press DISPLAY )((' ⇓ Press DISPLAY 5(7851 Temperature in the feed line. Temperature in the return line. & & ⇓ Press DISPLAY Difference in temperature between the feed and return lines. ⇓ Press DISPLAY 3($. 3 .: Peak power averaged over a 15 minute period.
Operation 15 ⇓ Press DISPLAY 23 70 ⇓ Operating time elapsed since the last reset. +5 0,1 Press DISPLAY ⇓ Press ACCUM TOTAL $&&80 +5 0,1 6833/< ⇓ &/2&. Time of day (24 hour clock). + 0,1 Press DISPLAY '$7( ⇓ Number of times the power has failed or has been switched off to the unit since the last reset. Press DISPLAY ⇓ Accumulated operating time (non-resettable).
16 Operation ⇓ Press ACCUM TOTAL (1 /2* * Energy Total of selected log entry. .:+ If logging is not used, pressing the DISPLAY key will return to the Energy display.
Operation 17 3.1.2 Charge/Discharge Operation If Charge/Discharge operation is programmed, the following display formats will be apparent in place of the normal ENERGY display: (1 &+5 ⇓ .:K ⇓ Press DISPLAY Charge Energy default display Charge Energy measured since the last reset. Press ACCUM TOTAL $&&80 (1 ',6 ⇓ .:K Discharge Energy measured since the last reset. .
18 Operation 3.1.3 Peak and Off-Peak Operation If Peak and Off-Peak operation is programmed, the following display formats will be apparent in place of the normal ENERGY display: (1 3. Peak Energy default display - Peak Energy measured since the last reset. .:K ⇓ Press DISPLAY ⇓ Press ACCUM TOTAL $&&80 .:K Accumulated Peak Energy Total (non-resettable). Off-Peak Energy measured since the last reset. (1 23.
Operation 19 3.2 CHECKING SET-UP PARAMETERS By pressing the DISPLAY key for 5 seconds, the program will enter the Check Set-up Parameters mode. Various set-up parameters can be checked, but not changed, by using the DISPLAY key. Set-up Mode may be exited by either moving to the last set-up item, QUIT, and selecting YES, or the DISPLAY key may be pressed and held for 5 seconds. After this time, the Model 212 will return to normal operation.
20 6. 7. Operation Parameter Value Description OFFSET x.x YES The offset between temperature sensors (see Section 3.5). 0.0 NO The offset function is disabled. Feed Ret Location of the flowmeter in either the feed or return line. FM LOC If High and Low alarms are installed 8. REL0 Flw H Flw L Pwr H Pwr L ∆t° H ∆t° L Ft° H Ft° L Rt° H Rt° L Defines the parameter for Relay 0 output as being high or low alarm for flow, power, temperature difference, feed or return temperatures. 9.
Operation Parameter Value 21 Description If 4-20mA Output is installed 8. 4-20mA Flow Pwr ∆t° Ft° Rt° Defines the parameter to be output as a 4-20mA signal. 9. 4mA xxxx.xxx Flowrate or temperature which corresponds to 4mA. 10. 20mA xxxx.xxx Flowrate or temperature which corresponds to 20mA. 12. PULSE Ener Volu Defines whether the pulse output is for the energy or volume total. 13. PULSE xxx.x kWh Defines how often a pulse is output (maximum frequency = 49Hz). 14.
22 18. Operation Parameter Value Description Df DIS YES Display will revert to Energy Total if no key has been pressed for 10 seconds. NO Display will stay on the last displayed parameter. 19. Fr RES YES NO Enable RESET key on front panel. Disable RESET key. 20. PK/OPK OFF ON Indicates whether Energy will be totalised in separate Peak and Off-Peak registers. (Only displayed if mode is set to Heat, Cool or Heating/Cooling.) 21.
Operation 24. 23 Parameter Value Description RESOL NORM Display Energy, Volume and Temperatures with normal resolution. HIGH Display Energy, Volume and Temperatures with high resolution for testing purposes (EN1434-2). Energy and Volume will be displayed as floating point values in Joule and m3 units respectively. Temperatures will be displayed with two decimal places. 25. S/WARE x.xx Software revision number. 26. QUIT YES Return to normal operation upon pressing the DISPLAY key.
24 Operation 3.3 UNITS OF MEASUREMENT The Model 212 can be programmed to operate in both metric and US units. The units which are displayed are fully programmable during the Set-up routine. Metric Energy Power Volume Flow Temperature kWh kW litres l/min °C MWh MW m3 m3/min MJ GJ MJ/hour GJ/hour kBTU KBTU/min gallon gal/min °F ton x hour therm KBTU/hour ton therm/min ft3 ft3/min ft3/hour m3/hour US Units Energy Power Volume Flow Temperature Note: Gallons are US Gallons.
Operation 25 3.4 FREQUENCY CUT-OFF A frequency cut-off can be programmed to prevent registering very low flow signals which may be the result of spurious pulses or a drift in the zero point of a flowmeter, such as magnetic flowmeter. Input frequencies at or below the cut-off are not registered and no flow is totalised.
26 Operation 3.5 OFFSET FUNCTIONS The offset function is designed for air conditioning systems with a very low ∆t. Often, in these systems, a bypass valve is installed to enable any differences in the feed and return temperature to be zeroed out. To compensate for any offset in the temperature sensors the Model 212 must be put into the Set-up Program mode. The bypass valve "A" is then opened and the valves "B" and "C" are closed.
Operation 27 3.6 OPERATING MODES The Model 212 may be programmed to operate in either of four modes, as follows: 1. 2. 3. 4. Heating Cooling Heating/Cooling Charge/Discharge. 3.6.1 Heating Heating mode is used when the application is for Heating only and assumes that the Feed Temperature will always be higher than the Return Temperature (positive ∆t). If the Feed Temperature is lower than the Return Temperature (negative ∆t), then no Energy is totalised, but Volumetric Flow is still totalised. 3.6.
28 Operation 3.6.4 Charge/Discharge Charge/Discharge mode is used when it is necessary to maintain two Energy totals. One for when ∆t is positive and one for when ∆t is negative. Only one total at a time is used.
Operation 29 3.7 PEAK AND OFF-PEAK When the Model 212 is programmed for either Heating, Cooling or Heating and Cooling, it is possible to program Peak and Off-Peak times. This enables the Model 212 to record Energy totals in two separate registers, depending on the time of day. A 24 hour period can be programmed as having one peak period and one off-peak period. For example, if "PEAK ON" is programmed as 09 and "PEAK OFF" is programmed as 18, then between 9.00am and 6.
30 Operation 3.8 LOGGING The Model 212 has the facility to log the current Energy total at fixed intervals which can be programmed to hour, day, week or month. HOUR DAY WEEK MONTH A log entry will occur at 00 minutes each hour. A log entry will occur at 00 hours 00 minutes each day. A log entry will occur at 00 hours 00 minutes each Monday. A log entry will occur at 00 hours 00 minutes on the 1st of the month. A total of 31 log entries can be stored and viewed by the Model 212.
Communications 31 4. COMMUNICATIONS Three modes of communications are provided: 1. Meter-bus. 2. Infra-red Communications link using M-Bus protocol. 3. RS485 with Modbus RTU protocol. Terminals 24 and 25 provide a connection for both the Meter-bus and the RS485. Links on the main board determine which interface is selected as follows: B A Link 4 Meter-bus Link 5 Link 4 RS485 Link 5 These links are accessible by removing the front panel as detailed in section 7.
32 Communications 4.1 METER-BUS The Model 212 serves as a secondary station in communications and includes the Meter-bus hardware and protocol according to IEC 870-5 and as detailed in EN 1434-3 with variable data format for reading out all parameters. Hardware The Meter-bus connection is available through galvanically isolated terminals 24/25 (irrespective of polarity) or optical interface (optional). The levels of input voltage/output current are as detailed in EN 1434-3.
Communications 33 Reception Frames* SEND (normalise): 10 40 ADR CS 16 REQUEST (data): 10 5B/7B ADR CS 16 SEND (data): 68 LEN 53/73 ADR LEN 68 51/55 DATA... CS 16 DATA...
34 Communications 4.2 INFRA-RED COMMUNICATIONS LINK The infra-red communication option uses the Meter-bus protocol as defined in IEC 870-5 and as detailed in EN 1434-3. This function is not implemented at this time.
Communications 35 4.3 RS485 WITH MODBUS RTU PROTOCOL Modbus RTU is an industry standard protocol which allows the Model 212 to be easily interfaced to DCS or PLC, or to computers running supervisor software systems. The Model 212 serves as a slave station in communications and includes the RS485 hardware and implementation of the standard protocol according to Modicon Modbus Protocol (RTU-mode) and as detailed in PI-MBUS-300 Rev F. Implementation specific details are as follows. 4.3.
36 Communications Except for broadcast messages, when a master device sends a query to a slave device it expects a normal response. One of four possible events can occur from the master's query: 1. If the slave device receives the query without a communication error, and can handle the query normally, it returns a normal response. 2. If the slave does not receive the query due to a communication error, no response is returned. The master program has to process a timeout condition for the query. 3.
Communications 37 4.3.4 Function Codes The Model 212 accepts the following function codes: Code Name Description 03 Read data register(s) Obtain the content of one or more 2 byte data registers. 06 Preset data register Preset one 2 byte data register. 07 Read status register Obtain the content of 1 byte status register. 16 Preset data register(s) Preset one or more 2 byte data registers. 4.3.
38 Communications Code Name Description 05 Acknowledge The slave has accepted the request and is processing it, but a long duration of time will be required to do so. 06 Slave device busy The slave is engaged in processing a long duration program command. The master should re-transmit the message later when the slave is free. 4.3.6 List of Data Registers The following list describes addresses and meaning of data registers for the Model 212.
Communications Address Name Value If High and Low Alarms are installed: 03 Relay 0 mode 00 - flow high 01 - flow low 02 - power high 03 - power low 04 - ∆t° high 05 - ∆t° low 06 - feed t° high 07 - feed t° low 08 - return t° high 09 - return t° low 04 Relay 1 mode 00 - flow high 01 - flow low 02 - power high 03 - power low 04 - ∆t° high 05 - ∆t° low 06 - feed t° high 07 - feed t° low 08 - return t° high 09 - return t° low If 4-20mA Output is installed: 03 4-20mA mode 00 - flow 01 - power 02 - ∆t
40 Communications Address Name Value Note 11 Peak mode 00 - off 01 - on 12 Peak on setpoint 00...23 13 Peak off setpoint 00...23 14 Logging mode 00 - off 01 - month 02 - week 03 - day 04 - hour 15 K-factor 0.001...999,999.9 FP 17 Cutoff frequency 0.01...0.99 FP If High and Low Alarms are installed: 19 Relay 0 setpoint 0.000...999,999.9 FP 21 Relay 1 setpoint 0.000...999,999.9 FP If 4-20mA Output is installed: 19 4mA setpoint 0.000...999,999.9 FP 21 20mA setpoint 0.
Communications Address Name Value Note 41 Elapsed time FP 43 Accumulated elapsed time FP 45 Power FP 47 Peak power FP 49 Volume flow FP 51 Not Used FP 53 Flow temperature FP 55 Return temperature FP 57 Temperature difference FP 59 Supply failures 60 Exception register 61 Logging point 1 - energy FP 63 Logging point 1 - time (seconds) since 01.01.1996 LI 181 Logging point 31 - energy FP 183 Logging point 31 - time (seconds) since 01.01.
42 Communications Address Name Value 187 Volume unit SI: 00 - ltr 01 - m3 US: 00 - gallon 01 - ft3 188 Power unit SI: 00 - MJ/hour 01 - GJ/hour 02 - kW 03 - MW US: 00 - kBTU/min 01 - kBTU/hour 02 - ton 03 - therm/min 04 - therm/hour 189 Volume flow unit SI: 00 - ltr/min 01 - m3/min 02 - m3/hour US: 00 - gallon/min 01 - ft3/min 02 - ft3/hour Note
Communications 43 Notes: FP This variable is represented in IEEE-754 Floating Point 4 byte format and requires two 2 byte data registers used as Modicon's floats: IEEE-754 1st byte 2nd byte 3rd byte 4th byte Modicon Registers low byte (register X) high byte (register X) low byte (register X+1) high byte (register X+1) This means that two data registers must be read/written to obtain/preset one data value.
44 Set-Up Mode 5. SET-UP MODE The Set-up Mode can only be entered by removing the lower cover strip (see Section 7). Usually this will mean breaking a seal which prevents the strip being removed without tampering. Once the strip is removed, a small hole provides access to a pushbutton. By inserting a pen tip or similar item into the hole and pressing the pushbutton, the instrument will enter the Set-up mode whereby the parameters can be entered or changed.
Set-up Mode 45 Parameter Value Description 4. UNITS SI US Metric units. US units. 5. ENERGY Set energy units for display. 6. VOLUM Set volume units for display. 7. POWER Set power units for display. 8. FLOW Set flow rate units for display. 9. FACTOR xxx.x p/ltr The K-factor of the flowmeter which has been programmed. (See flowmeter manufacturers data.) 10. CUTOFF x.xx Hz Low frequency cut-off of the flowmeter, expressed in Hz.
46 Set-up Mode Parameter Value Description If High and Low alarms are installed. 13. REL0 Flw H Flw L Pwr H Pwr L ∆t° H ∆t° L Ft° H Ft° L Rt° H Rt° L Defines the parameter for Relay 0 output as being high or low alarm for flow, power, temperature difference, feed or return temperatures. 14. REL0 xxxx.xxx Set point for parameters set in step 13 above. For low alarms the relay will close if the parameter is below the set point. For high alarms it will close if the parameter is above the set point.
Set-up Mode Parameter Value Description 15. 20mA xxxx.xxx Flowrate or temperature which corresponds to 20mA. 17. PULSE Ener Volu Defines whether the pulse output is for the energy or volume total. 18. PULSE xxx.x kWh Defines how often a pulse is output (maximum frequency = 49Hz). 19. CLOCK xx Hour/Min Set time in hours and minutes. Real time clock is able to run without power for two days typically. 20. DATE xxxx Set date in year, month and day.
48 25. Set-up Mode Parameter Value Description Df DIS YES Display will revert to Energy Total if no key has been pressed for 10 seconds. NO Display will stay on the last displayed parameter. 26. Fr RES YES NO Enable RESET key on front panel. Disable RESET key. 27. PK/OPK OFF ON Selects whether Energy will be totalised in separate Peak and Off-Peak registers. If set to OFF, Set-up continues at step 30. 28.
Set-up Mode 31. 32. 49 Parameter Value Description RESOL NORM Display Energy, Volume and Temperatures with normal resolution. HIGH Display energy, Volume and Temperatures with high resolution for testing purposes (EN1434-2). Energy and Volume will be displayed as floating point values in Joule and m3 units respectively. Temperatures will be displayed with two decimal places. YES Return to normal operation upon pressing the DISPLAY key. NO Continue in the Set-up mode.
50 Input & Output Connections 6. INPUT & OUTPUT CONNECTIONS 6.1 FLOWMETER INPUT The instrument will accept frequency or pulse inputs from a wide range of flowmeters. Examples of connection diagrams are shown on the following pages. Note that it may be necessary to change the position of the links as shown. These links are accessible by removing the front panel as detailed in section 7.2 and the link positions are shown in the drawing in section 7.3.
Input & Output Connections 1. Pulse 2. Reed Switch 3. Coils eg. mV signals from turbine flowmeters or paddlewheels.
52 Input & Output Connections 4. Opto-Sensors 5.
Input & Output Connections 53 6.2 RTD INPUT The Model 212 uses four wire RTDs to provide optimum accuracy and stability. The RTDs are high grade 100 ohm platinum types manufactured to BS1094 standards. It is not necessary with four wire RTDs to have equal lead lengths, but cables should not be longer than 50 meters (150 feet).
54 Input & Output Connections 6.3 POWER SUPPLY The Model 212 will operate from a central 12-24 Volts dc source and typically draws around 60mA. A power adapter is supplied as standard and this supply can also be used to power the flowmeter, alarms and peripheral items. The flexible power supply system allows: 1. The Model 212 to be operated from a low cost power adapter. 2. Multiple units to be powered from a single power source. 3.
Input & Output Connections 55 6.4 PULSE OUTPUT A pulse output is available on terminals 16 and 17. The output is an open collector transistor suitable for external counters.
56 Input & Output Connections The output on terminal 16 is capable of sinking up to 100mA maximum and can withstand external voltages of 30 Volts. Reverse polarity and inductive load protection is provided. Two connection examples are provided. If a voltage pulse output is required, an external load resistor must be used as shown on the second diagram. The pulse output can be programmed during Set-up as an energy or volumetric flow output.
Input & Output Connections 57 6.5 ALARM RELAY OUTPUTS Note that the High/Low alarms are not available when the 4-20mA output option is installed. Two Solid State dc relays are provided as alarm outputs. These relays are fully isolated and can be used to drive external relays, lamps, audible alarms, etc.
58 Input & Output Connections For example, Relay 0 can be programmed to alarm if the flow rate is below a certain value, while Relay 1 can be programmed to alarm if the power consumption exceeds a preset value. In the alarm condition the relays are closed, and are open in the non-alarm condition or when the instrument is unpowered.
Input & Output Connections 59 6.6 4-20mA OUTPUT OPTION A 4-20mA Output Option is available and can be used to retransmit the volumetric flowrate, energy flowrate, temperature difference, feed temperature and return temperature. The maximum output voltage is the supply voltage less 6 volts. Therefore the maximum load resistance can be calculated as: Maximum Load = Supply - 6 0.02 At 24 volts, Rmax = 900 ohms and at 12 volts, Rmax = 300 ohms.
60 Input & Output Connections The output specifications are: Current Range: Linearity & Resolution: Accuracy: Response Time: 2.0mA to 22.0mA. 0.02% of span. 0.1% of span. 0.5 seconds to 99% of step. The output can be programmed to output the following: Volumetric Flowrate Energy Flowrate (power) Feed Temperature Return Temperature Temperature Difference The 4mA point and 20mA point can be individually programmed during setup.
Installation 61 7. INSTALLATION 7.1 WALL MOUNTING A wall mounting bracket is supplied with each instrument. A drilling diagram is outlined on the following page.
62 Input & Output Connections
Installation 63 7.2 PANEL MOUNT VERSION The panel mount version of the Model 212 is supplied with two panel mount brackets and plug-in terminals which are accessible from the rear of the instrument. A diagram of the rear panel is shown below. Note that access to the Input Circuit Links 1-3 and Communication Links 4-7 can only be obtained by opening the instrument. Access is not available via the rear panel. The cutout for the panel mount version is 141mm (5.55") wide x 87mm (3.43") high.
64 Installation 7.3 REMOVING THE FRONT PANEL The front of the instrument is removed as follows: 1. Remove both the top and bottom cover strips (ie. the dark plastic strips on the front) by using a screwdriver to lever up one end. 2. Undo the seven screws retaining the front. Note: The screws should not be removed from the front panel as they are retained by O-rings. 3. Pull the front panel free from the housing. Replacing the front panel of the instrument is the reverse procedure.
Installation 65
66 Installation 7.4 VERIFICATION SEAL A Verification Seal is supplied with the instrument and can be placed across the calibration switch to prevent unauthorised tampering. The seal is made from a self adhesive material which is destroyed if the seal is broken.
Installation 67 7.5 WIRING PRACTICES Three of the terminals are marked using a multi-stranded, braided wire. and must be connected to a good earth, It is good wiring practice to use shielded cables for all connections to the Model 212. Care must be taken to separate signal cables from power cables and relay cables, so as to minimise interference. Overall shields should be connected at the instrument side only and to the terminals marked . These connections should be as short as possible.
68 Installation Termination Board
Installation 7.6 TERMINAL DESIGNATIONS Terminal numbering is in accordance with international standards.
70 Index Index A ACCUM TOTAL Key, 12 Accuracy Class, 7 Alarm Relay Outputs, 57 B Batteries, 54 BTU, 6 Bus Address, 21 Bus Hardware, 21 C Cable Length, 8 Charge/Discharge, 28 Check Set-up Parameters, 19 Coils, 51 Communications, 31 Connections, 50 Construction, 9 Conversion Factors, 6 Cooling, 27 Cover Strips, 64 Cut-off, 25 D DISPLAY Key, 12 Display Mode, 11 E EMC, 4 EMC Directive, 67 Emission, 4 EN1434, 3 Energy Measured, 13, 17, 18 Enthalpy, 3 F Flowmeter Input, 50 Frequency Cut-off, 19, 25 H Hea
Index Pulse Output, 21, 55 R Reed Switch, 51 Relay, 20 Relays, 57 RESET Key, 12 Reverse Polarity, 56 RS485, 35 RTD Input, 53 S Sensor Type, 8 Set-up Mode, 44 Set point, 20 Shielded Cables, 67 Shields, 67 Software Revision, 23 Solid State dc Relays, 57 Specification, 7 T Temperature Difference, 7 Temperature Range, 7 Terminal Designations, 69 Termination Board, 68 Ton, 6 U Units of Measurement, 24 V Verification Seal, 66 W Wall Mounting, 61 Wiring Practices, 67 Z Zero, 26 71
