HEAT CALCULATOR
MODEL 212
July 1998
CONTENTS
1. Overview 3
1.1 Model Number Designation 5
1.2 Conversion Factors 6
2. Specification 7
3. Operation 11
3.1 Display Operation 13
3.1.1 Normal Operation 13
3.1.2 Charge/Discharge Operation 17
3.1.3 Peak and Off-Peak Operation 18
3.2 Checking Set-up Parameters 19
3.3 Units of Measurement 24
3.4 Frequency Cut-off 25
3.5 Offset Functions 26
3.6 Operating Modes 27
3.6.1 Heating 27
3.6.2 Cooling 27
3.6.3 Heating/Cooling 27
3.6.4 Charge/Discharge 28
3.7 Peak and Off-Peak 29
3.8 Logging 30
4. Communications 31
4.1 Meter-bus 32
4.2 Infra-red Communications Link 34
4.3 RS485 with Modbus RTU Protocol 35
4.3.1 Hardware 35
4.3.2 Protocol 35
4.3.3 Bus Address 36
4.3.4 Function Codes 37
4.3.5 Exception Response 37
4.3.6 List of Data Registers 38
5. Set-up Mode 44
6. Input & Output Connections 50
6.1 Flowmeter Input 50
6.2 RTD Input 53
6.3 Power Supply 54
6.4 Pulse Output 55
6.5 Alarm Relay Outputs 57
6.6 4-20mA Output Option 59
7. Installation 61
7.1 Wall Mounting 61
7.2 Panel Mount Version 63
7.3 Removing the Front Panel 64
7.4 Verification Seal 66
7.5 Wiring Practices 67
7.6 Terminal Designations 69
Index 70
)
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.
The Model 212 measures the temperature in the feed and return flow lines and
uses this information to calculate the density and enthalpy of water. By also
measuring the volume of water flowing in the system, the Model 212 will then
determine the energy used. Power is calculated as:
P=Vxρ x(h
TV-hTR
where P = Power (W)
3
V = Volumetric Flow rate (m
!
= density (kg/m
= Specific Enthalpy (J/kg) at Feed Temperature
h
TV
= Specific Enthalpy (J/kg) at Return Temperature
h
TR
3
)
/sec)
The Model 212 is designed to be used in typical water heating or cooling systems
where pressures do not exceed 16 bars.
The temperature in both the feed and return lines is measured via two PT100
resistance temperature devices (RTDs). For maximum accuracy, four wire RTD
measurement is used and internally corrected for non-linearities which are
inherent to an RTD.
The Model 212 complies with OIML R75 and EN1434 standards and includes
Meter-bus and an infra-red data transfer option.
The Model 212 includes separate peak and off-peak registers as well as the ability
to compute charge and discharge energy in systems where heat may be stored in
underground tanks. The Model 212 also includes an RS485 communications link
with Modbus RTU protocol.
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.
Generic Emission Standard EN 50081-2 Industrial Environment.
Generic Immunity Standard EN 50082-1 Residential, Commercial & Light
Industry Environment.
Generic Immunity Standard EN 50082-2 Industrial Environment.
In order to comply with these standards, the wiring instructions in Section 7.5
must be followed.
1.1 MODEL NUMBER DESIGNATION
Model 212 . 2 0 E 8 S
Mounting
Panel Mount 1
Wall Mount 2
Options
No Options 0
4-20mA Output 1
Power
12VDC Power N
European Adapter
(220 VAC) E
UK Adapter
(220 VAC) U
USA Adapter
(110 VAC) A
Australian Adapter
(240 VAC) H
Overview 5
Temperature Sensor
None 0
85mm pipe 8
120mm pipe 1
210mm pipe 2
Compliance
EN1434 S
6 Overview
1.2 CONVERSION FACTORS
1 kWh = 3.600 MJ
1 MJ = 0.27778 kWh
3
1 m
1 US gal = 3.785 litres
3
1 ft
1 kBTU = 1.0551 MJ
1 Ton x Hour (Refrigeration) = 12,000 BTU
1 therm = 100,000 BTU
Note: kBTU are used on the Model 212 display and mean BTU x 1000.
= 1000 litres
= 7.4805 US gal
Specification 7
2. SPECIFICATION
General
Energy Display units: kWh, MWh, MJ, GJ, therm, BTU x 1000,
tons x hours (refrigeration).
Maximum Thermal
Power: 3000 MW.
Accuracy Class: OIML R75 Class 4,
EN1434.
Measurement Time: 0.5 sec time interval.
Environmental Class: EN1434 Classes A & C.
Ambient Temp Range: 0°C to 60°C.
Storage Temp Range: -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.
Approved Temp Range: 1°C to 200°C.
Approved Temp Difference: 3K to 199K.
Measurement Time: 3 sec time interval.
Display
Type: LCD with 7 digit numeric display and 11
character display.
Digits: 15.5mm (0.6") high.
Characters: 6mm (0.24") high.
8 Specification
Flowmeter Input
Type: Frequency or Pulse between 0.01Hz to 20kHz.
Default low frequency cut-off is 0.25Hz.
Signal Type: Pulse, open collector, reed switch, proximity
switch or coil.
K-factor range: Programmable between 0.001 to 999,999.9 pulse
3
per litre, m
, US gallon or ft3.
Location: In either the feed or return lines.
Temperature Sensor (RTD) Input
Sensor Type: Pt100 to IEC 751.
Connection Type: Four wire.
Location: Two RTD inputs, one for the feed and a second
for the return lines.
Linearisation: Built in RTD linearisation.
Temperature Range: -10°C to 220°C.
RTD Cable Length: < 50m.
Pulse Out
Pulse Width: 10ms.
Type: Open collector will sink up to 100mA.
30Vdc Maximum.
Function: Volume or Energy (scaled).
Frequency: 1 pulse every preset number of units of energy or
volume total.
Power Requirements
dc Power: 12 to 24V dc @ 100mA maximum.
ac Power: Supplied via a power adapter.
Specification 9
Construction
Enclosure Material: ABS/Polycarbonate.
Colour: Light beige.
Protection: Sealed to IP67 (Nema 4X).
Mounting: Wall mounting or panel mounting.
Dimensions: 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: Two solid state opto-isolated relays which will
sink up to 250mA. 30V dc maximum.
Function: High and low alarms individually programmable
as unsigned values, for volumetric flow rate,
energy flow rate, feed temperature, return
temperature or temperature difference.
4-20mA Output Option
Function: Volumetric flowrate, energy flowrate, feed
temperature, return temperature or temperature
difference.
Output Range: 2.0mA to 22.0mA.
Linearity: 0.02% of span.
Accuracy: 0.1% of span.
Response Time: 0.5 seconds to 99%.
Maximum Output: Vdc -6V.
10 Specification
RS485 Option
Data Transmitted: Volume and energy totals, peak power,
temperatures.
Baud rate: 300 - 9600 baud.
Parity: Odd, even or none.
Stop bits: One or two stop bits.
Bus Address: Programmable for multiple instruments on the
same bus.
Protocol: Modbus RTU.
Meter-Bus
Type: Conforms to CEN/TC176 Meter-bus standard.
Protocol: IEC 870-5.
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. The DISPLAY key is used
to step through the parameter list.
3. Set-up Parameters.
By removing the bottom cover strip of the instrument (see Section 7),
the set-up switch becomes visible. Pressing this switch will put the
instrument into the set-up mode, whereby all parameters can be
programmed using the DISPLAY, and switches.
Operation 11
The LCD display has 7 numeric digits with 11 alphanumeric characters along the
bottom. The alphanumeric characters are used to display the parameter and
units.
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.
Also increments the digit, changes decimal point
position, steps through units when entering set-up
parameters and steps through individual log
entries.
Used to change the display to the next parameter.
Also steps through display modes when held for 5
seconds.
Operation 13
3.1 DISPLAY OPERATION
3.1.1 Normal Operation
Data which can be displayed by pressing the DISPLAY key is as follows:
Default display - Energy measured
since the last reset.
(1(5*< .:K
Press DISPLAY Press ACCUM TOTAL
⇓⇓
Accumulated Energy
Total (non-resettable).
$&&80 .:K
7(67
Press DISPLAY
⇓
92/80( 0
Press DISPLAY Press ACCUM TOTAL
⇓⇓
Display segments test. Segments are
flashing.
Volume of water measured through
the system since the last reset.
Accumulated Volume
Total (non-resettable).
$&&80 0
14 Operation
32:(5 .:
Press DISPLAY
⇓
Energy flow rate
)/2: 0+
Press DISPLAY
⇓
)((' &
Press DISPLAY
⇓
5(7851 &
Press DISPLAY
⇓
Volume flow rate
Temperature in the feed line.
Temperature in the return line.
Difference in temperature between
the feed and return lines.
Press DISPLAY
⇓
3($. 3 .:
Peak power averaged over a 15
minute period.
Press DISPLAY
⇓
Operating time elapsed since the last
reset.
23 70 +50,1
Press DISPLAY Press ACCUM TOTAL
⇓⇓
Operation 15
$&&80 +50,1
6833/<
Press DISPLAY
⇓
&/2&. +0,1
Press DISPLAY
⇓
'$7(
Press DISPLAY*
⇓
Accumulated operating
time (non-resettable).
Number of times the power has failed
or has been switched off to the unit
since the last reset.
Time of day (24 hour clock).
Date - Day - Month (SI Units)
Month - Day (US Units)
70 /2*
Time and date of the last logged
entry. Pressing the RESET key will
display the previous logged entries.
16 Operation
Press ACCUM TOTAL
⇓
Energy Total of selected
log entry.
(1 /2* .:+
* 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 Press ACCUM TOTAL
⇓⇓
$&&80 .:K
Charge Energy default display Charge Energy measured since the
last reset.
Accumulated Charge
Energy Total
(non-resettable).
Discharge Energy measured since the
last reset.
(1 ',6 .:+
Press DISPLAY Press ACCUM TOTAL
⇓⇓
Accumulated Discharge
Energy (non-resettable).
$&&80 .:+
Press DISPLAY Press ACCUM TOTAL
⇓⇓
Display segments test. Segments are
7(67
⇓
Press DISPLAY
For continuation of displays refer to Section 3.1.1 Normal Operation.
flashing.
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. .:K
Press DISPLAY Press ACCUM TOTAL
⇓⇓
$&&80 .:K
Peak Energy default display - Peak
Energy measured since the last reset.
Accumulated Peak
Energy Total
(non-resettable).
Off-Peak Energy measured since the
last reset.
(1 23.
Press DISPLAY Press ACCUM TOTAL
⇓⇓
Accumulated Off-Peak
Energy (non-resettable).
$&&80 .:+
Display segments test. Segments are
flashing.
7(67
⇓
Press DISPLAY
For continuation of displays refer to Section 3.1.1 Normal Operation.
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.
The readout will display the following:
Parameter Value Description
1. LANG ENGL
GERM
Current language.
2. MODE HEAT
COOL
HT/CL
CHAR
3. UNITS SI
US
4. FACTOR xxx.x p/ltr The K-factor of the flowmeter which has
5. CUTOFF x.xx Hz Low frequency cut-off of the flowmeter
Current mode of operation.
Metric units.
US units.
been programmed.
expressed in Hz. The Model 212 will not
register flow if the input frequency is
below this value. (Default is 0.25Hz).
See Section 3.4.
20 Operation
Parameter Value Description
6. OFFSET x.x
YES
The offset between temperature sensors
(see Section 3.5).
0.0
NO
7. FM LOC Feed
Ret
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
9. REL0 xxxx.xxx Set point for parameters set in step 8
The offset function is disabled.
Location of the flowmeter in either the
feed or return line.
Defines the parameter for Relay 0 output
as being high or low alarm for flow,
power, temperature difference, feed or
return temperatures.
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.
10 REL1 ... Defines the parameter for Relay 1 as in
step 8 above.
11. REL1 xxxx.xxx Set point for parameter for Relay 1 as in
step 9 above.
Operation 21
Parameter Value Description
If 4-20mA Output is installed
8. 4-20mA Flow
Pwr
∆t°
Ft°
Rt°
9. 4mA xxxx.xxx Flowrate or temperature which
10. 20mA xxxx.xxx Flowrate or temperature which
Defines the parameter to be output as a
4-20mA signal.
corresponds to 4mA.
corresponds to 20mA.
12. PULSE Ener
Volu
13. PULSE xxx.x kWh Defines how often a pulse is output
14. COMMS NONE
M-BUS
RS485
15. BAUD xxxx Communications baud rate between 300
16. PARITY Even/Odd/None Communications parity.
17. BUS xx ADDR Bus address for the communications link.
Defines whether the pulse output is for
the energy or volume total.
(maximum frequency = 49Hz).
No Communications.
Meter-bus (see Section 4).
Modbus RTU.
and 9600.
22 Operation
Parameter Value Description
18. Df DIS YES
Display will revert to Energy Total if no
key has been pressed for 10 seconds.
NO
19. Fr RES YES
NO
20. PK/OPK OFF
ON
21. PK ON xx
hour
22. PK OFF xx
hour
Display will stay on the last displayed
parameter.
Enable RESET key on front panel.
Disable RESET key.
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.)
Sets the hour at which energy totalisation
will commence in the PEAK register.
(Only displayed if mode is set to Heat,
Cool or Heating/Cooling and PK/OPK is
set to ON.)
Sets the hour at which energy totalisation
will commence in the OFF PEAK
register. (Only displayed if mode is set
to Heat, Cool or Heating/Cooling and
PK/OPK is set to ON.)
23. LOG OFF
MONTH
WEEK
DAY
HOUR
Selects the interval at which Logging
will take place.
Parameter Value Description
24. RESOL NORM
Operation 23
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 m
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.
NO
Continue in the Check Set-up mode. To
continue use the key to select NO
and then press the DISPLAY key.
3
units
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 kWh MWh MJ GJ
Power kW MW MJ/hour GJ/hour
Volume litres m
Flow l/min m3/min m3/hour
Temperature °C
US Units
Energy kBTU ton x hour therm
Power KBTU/min KBTU/hour ton therm/min therm/hour
Volume gallon ft
Flow gal/min ft3/min ft3/hour
Temperature °F
3
3
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.
The relationship between the flow rate at cut-off and the frequency is:
frequency (Hz) =
flow rate x K-factor
time base
where time base = 60 if the flow rate is in units/min and 3600
if the flow rate is in units/hour.
flow rate = flow rate at the cut-off.
K-factor = pulses per unit for the flowmeter.
For example, if the required cut-off is 50 l/h and the K-factor for the flowmeter is
63, then the cut-off frequency:
50x63
f=
3600
= 0.88Hz.
Generally, at frequencies above 0.25Hz, the cut-off is left at the default value of
0.25Hz. However, some water meters produce relatively low frequencies and the
cut-off may need to be programmed to a frequency less than 0.25Hz.
Note: Be careful when setting low cut-off values below 0.25Hz, since the
display update time on the flow rate and power will become long. For
example, if the cut-off is set to 0.01Hz, the instrument will continue to
display the flow rate for 100 seconds, if the signal stops. This is
because the time interval between the signal at 0.01Hz is 100 seconds
and the Model 212 must wait this long before it can determine that the
flow has actually stopped.
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.
With offset selected, the user then enters YES to zero the offset between the feed
and return lines. The measured offset will then be displayed on the Model 212,
the value of which will be stored when the Set-up Mode is exited.
The system is then returned to normal by closing valve "A" and opening valves
"B" and "C".
Operation 27
3.6 OPERATING MODES
The Model 212 may be programmed to operate in either of four modes, as
follows:
1. Heating
2. Cooling
3. Heating/Cooling
4. 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.
3.6.2 Cooling
Cooling mode is used when the application is for Cooling only and assumes that
the Feed Temperature will always be lower than the Return Temperature
(negative ∆t). If the Feed Temperature is higher than the Return Temperature
(positive ∆t), then no Energy is totalised, but Volumetric Flow is still totalised.
3.6.3 Heating/Cooling
Heating/Cooling mode is used where the flow of Energy may be for Heating or
Cooling. In this mode Energy is increased regardless of whether ∆t is positive or
negative.
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 6.00pm totalisation would occur in
the Peak register and between 6.00pm and 9.00am, totalisation would occur in
the Off-Peak register.
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 A log entry will occur at 00 minutes each hour.
DAY A log entry will occur at 00 hours 00 minutes each day.
WEEK A log entry will occur at 00 hours 00 minutes each Monday.
MONTH 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.
After 31 entries have been completed, the oldest logged entry is overwritten by
the newest logged entry, therefore only the 31 most current logged entries are
kept.
Logging facilities are only available if the mode of operation is set to Heating,
Cooling or Heating/Cooling without Peak/Off-Peak Energy registers.
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:
BA
Link 4
Meter-bus
Link 5
Link 4
RS485
Link 5
These links are accessible by removing the front panel as detailed in section 7.2
and the link positions are as shown in the drawing in section 7.3. Links are
made via small black caps which fit over the connecting posts, thereby creating a
link.
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.
Bus Address
The bus address of the Model 212 is programmable in range between 0 to 250.
Some addresses are reserved according to EN 1434-3 and have a special
meaning:
0 default address for unconfigured meter
251...253 reserved
254 answer regardless of own address
255 broadcast, no response.
Protocol
The protocol uses asynchronous serial bit transmission in half-duplex mode with
1 start bit, 8 data bits, 1 even parity bit, 1 stop bit and programmable baud rate
(300 to 9600 baud). Link service classes S2 (SEND/CONFIRM) and S3
(REQUEST/RESPOND) are provided utilising frame format class FT1.2
according to IEC 870-5.
This protocol incorporates a frame counter bit (FCB) which has to be toggled by
primary station if the last communication was undisturbed. The Model 212 keeps
a copy of the last transmitted CONFIRM or RESPOND frame in order to
retransmit it if the next FCB has not been toggled.
Communications 33
Reception Frames*
SEND (normalise):
10 40 ADR CS 16
REQUEST (data):
10 5B/7B ADR CS 16
SEND (data):
68 LEN LEN 68 53/73 ADR 51/55 DATA... CS 16
Transmission Frames*
CONFIRM (acknowledgment of NORMALISE):
E5
CONFIRM (acknowledgment):
10 00 ADR CS 16
CONFIRM (no acknowledgment, link busy):
10 01 ADR CS 16
RESPOND (no acknowledgment, data is not available):
10 09 ADR CS 16
RESPOND (data)
68 LEN LEN 68 08 ADR 72 DATA... CS 16
* byte values are represented in the hexadecimal format.
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.
4.3.1 Hardware
The Modbus connection is available on terminals 24/25 and links 4 and 5 must
be connected as described at the beginning of this chapter.
4.3.2 Protocol
The protocol uses asynchronous serial bit transmission in half duplex mode with
1 start bit, 8 data bits and (1 parity bit + 1 stop bit) or 2 stop bits depending on
whether the parity check has been programmed to "NONE" or not. The baud rate
is programmable in range from 300 to 9600 Baud. The parity check can be
programmed to Even, Odd or None. Link service classes SEND/CONFIRM and
REQUEST/RESPOND are provided utilising frame formats according to
PI-MBUS-300.
In RTU mode, messages start with a silent interval of at least 3.5 character time.
Following the last transmitted character, a similar interval of at least 3.5
character times marks the end of the message. A new message can begin after
this interval. The entire message frame must be transmitted as a continuous
stream. A typical message frame is shown below:
ADDRESS FUNCTION DATA CRC CHECK
1 byte 1 byte N bytes 2 bytes
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. If the slave receives the query, but detects a communications error
(parity or CRC), no response is returned. The master program has to
process a timeout condition for the query.
4. If the slave receives the query without a communication error, but
cannot handle it (for example, if the request is to read a nonexistent
register), the slave will return an exception response informing the
master of the nature of the error.
4.3.3 Bus Address
The bus address of the Model 212 is programmable in range between 1 to 247.
Some addresses are reserved according to PI-MBUS-300 and have a special
meaning:
0 Broadcast, no response
247...255 Reserved
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.
4.3.5 Exception Response
The Model 212 forms an exception response by adding 80H to the function code
and using an exception code as the 1 byte data field in the returned frame.
Implemented exception codes are as follows:
Code Name Description
01 Illegal function The function code is not a
legal action for the slave.
02 Illegal data address The data address is not a legal
address for the slave.
03 Illegal data value The data value is not a legal
value for the slave.
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. Engineering units programmed during setup are used for floating
point values. Conventional numbering of registers often starts from 1, therefore
be aware that "register 1" in this case has an "address 0" and so on.
Read and Write Registers
Address Name Value Note
00 Heating mode 00 - heat
01 - cool
02 - heat/cool
03 - charge/discharge
01 Total reset 00 - no action
01 - reset totals
02 Flowmeter location 00 - feed line
01 - return line
Communications 39
Address Name Value Note
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°
03 - feed t°
04 - return t°
05 Pulse out mode 00 - volume
01 - energy
06 Year 00...99 (when writing)
07 Month 01...12
08 Day 01...31
09 Hour 00...23
10 Minute 00...59
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 0.000...999,999.9 FP
23 Pulse out setpoint 0.000...999,999.9 FP
Read Only Registers
Address Name Value Note
25 Energy 0 FP
27 Energy 1 FP
29 Accumulated energy 0 FP
31 Accumulated energy 1 FP
33 Volume FP
35 Accumulated volume FP
37 Not Used FP
39 Not Used FP
Communications 41
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 00 - no failure
01 - RTD failure
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 01.01.1996 LI
185 K-factor unit SI: 00 - pulse/ltr
01 - pulse/m
3
US: 00 - pulse/gallon
01 - pulse/ft
3
186 Energy unit SI: 00 - MJ
01 - GJ
02 - kWh
03 - MWh
US: 00 - kBTU
01 - ton x hour
02 - therm
42 Communications
Address Name Value Note
187 Volume unit SI: 00 - ltr
3
01 - m
US: 00 - gallon
3
01 - ft
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
3
/min
01 - m
3
/hour
02 - m
US: 00 - gallon/min
3
/min
01 - ft
3
/hour
02 - ft
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 Modicon Registers
1st byte low byte (register X)
2nd byte high byte (register X)
3rd byte low byte (register X+1)
4th byte high byte (register X+1)
This means that two data registers must be read/written to
obtain/preset one data value.
LI This variable is represented as a long integer in 4 byte format and
requires two 2 byte data registers:
Long Integer Modicon Registers
1st byte (MSB) high byte (register X)
2nd byte low byte (register X)
3rd byte high byte (register X+1)
4th byte (LSB) low 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.
The DISPLAY key is used to step through each parameter and the and
keys are used to step through and change items (digits, decimal points or units).
The item which can be changed flashes. Thus the instrument can be fully
programmed on-site without having to purchase a separate programmer.
If the Set-up access pushbutton is pressed while the Model 212 is in Set-up Mode,
the display will return to step 1.
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.
Parameter Value Description
1. LANG ENGL
GERM
2. MODE HEAT
COOL
HT/CL
CHAR
3. RESET NO
YES Resets totals upon exiting the Set-up
Select language.
Selects the mode of operation between
Heating, Cooling, Heating and Cooling
or Charge/Discharge.
Mode.
Set-up Mode 45
Parameter Value Description
4. UNITS SI
US
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
10. CUTOFF x.xx Hz Low frequency cut-off of the flowmeter,
Metric units.
US units.
been programmed. (See flowmeter
manufacturers data.)
expressed in Hz. The Model 212 will
not register flow if the input frequency is
below this value. Note that the default is
0.25Hz and it is recommended to not
change this value unless the flowmeter
produces very low frequencies. (See
Section 3.4.)
11. OFFSET x.x
YES
0.0
NO
12. FM LOC Feed
Ret
The offset between temperature sensors.
(See Section 3.5).
The offset function is disabled.
Location of the flowmeter as being in
either the feed or return line.
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
14. REL0 xxxx.xxx Set point for parameters set in step 13
15. REL1 ... Defines the parameter for Relay 1 as in
Defines the parameter for Relay 0 output
as being high or low alarm for flow,
power, temperature difference, feed or
return temperatures.
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.
step 13 above.
16. REL1 xxxx.xxx Set point for parameter for Relay 1 as in
step 14 above.
If 4-20mA Output is installed.
13 4-20mA Flow
Pwr
∆t°
Ft°
Rt°
14 4mA xxxx.xxx Flowrate or temperature which
Defines the parameter to be output as a
4-20mA signal.
corresponds to 4mA.
Set-up Mode 47
Parameter Value Description
15. 20mA xxxx.xxx Flowrate or temperature which
corresponds to 20mA.
17. PULSE Ener
Volu
18. PULSE xxx.x kWh Defines how often a pulse is output
19. CLOCK xx
Hour/Min
20. DATE xxxx
Year/Month/Day
21. COMMS NONE
M-BUS
RS485
22. BAUD xxxx Communications baud rate between 300
23. PARITY Even/Odd/None Communications parity (with Meter-bus
Defines whether the pulse output is for
the energy or volume total.
(maximum frequency = 49Hz).
Set time in hours and minutes.
Real time clock is able to run without
power for two days typically.
Set date in year, month and day.
Real time clock is able to run without
power for two days typically.
If no communications are to be used,
Set-up Mode continues at step 25.
Meter-bus (see Section 4).
Modbus RTU.
and 9600.
the parity is not changeable and is set to
even parity).
24. BUS xx ADDR Bus address for the communications
link.
48 Set-up Mode
Parameter Value Description
25. Df DIS YES
Display will revert to Energy Total if no
key has been pressed for 10 seconds.
NO
26. Fr RES YES
NO
27. PK/OPK OFF
ON
28. PK ON xx
hour
29. PK OFF xx
hour
30. LOG OFF
MONTH
WEEK
DAY
HOUR
Display will stay on the last displayed
parameter.
Enable RESET key on front panel.
Disable RESET key.
Selects whether Energy will be totalised
in separate Peak and Off-Peak registers.
If set to OFF, Set-up continues at step
30.
Sets the hour at which energy totalisation
will commence in the PEAK register.
(Only available if mode is set to Heat,
Cool or Heating/Cooling.)
Sets the hour at which energy totalisation
will commence in the OFF PEAK
register. (Only available if mode is set to
Heat, Cool or Heating/Cooling.)
Selects the interval at which Logging
will take place.
Logging is only available if the mode
(step 2) is set to Heating, Cooling or
Heating/Cooling and the Peak/Off-Peak
(step 27) is set to OFF. If logging is not
available, this step will not be displayed.
Parameter Value Description
31. RESOL NORM
Set-up Mode 49
Display Energy, Volume and
Temperatures with normal resolution.
HIGH
32. QUIT YES
NO
Display energy, Volume and
Temperatures with high resolution for
testing purposes (EN1434-2). Energy
and Volume will be displayed as floating
3
point values in Joule and m
units
respectively. Temperatures will be
displayed with two decimal places.
Return to normal operation upon
pressing the DISPLAY key.
Continue in the Set-up mode. To
continue use the key to select NO
and then press the DISPLAY key.
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.
Link 1 Links in an input filter for a reed switch. The
maximum input frequency is approximately 500Hz
with this filter.
Link 2 Link for coils (eg. turbine or paddlewheel flow
sensors).
Link 3 Not connected. This position is selected if links 1 or 2
are not required.
Link 6 Selects a two wire proximity switch when in position
B.
Link 7 Selects a coil input when in position B.
The links are made via small black caps which fit over the two connecting posts
thereby creating the link.
The input on terminals 10 or 11 is limited to 30 volts maximum.
Note: After connecting the flowmeter, it is also necessary to program the
flowmeter factor. This is supplied by the flowmeter manufacturer and
represents the number of pulses per litre, m3, gallon or ft3 that the
flowmeter outputs for each unit of volume. It is often referred to as the
K-factor.
1. Pulse
2. Reed Switch
Input & Output Connections 51
3. Coils eg. mV signals from turbine flowmeters or paddlewheels.
52 Input & Output Connections
4. Opto-Sensors
5. Namur Switch
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). They should be shielded twisted
pairs connected as follows:
Note: Care must be taken to ensure the (+) of the current terminal is
connected to the same side of the RTD as the (+) of the input terminal.
The RTD, itself, has no polarity.
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. Mains powered systems with battery backup to be easily implemented
using standard sealed lead acid batteries.
By separating the ac power from the main Model 212, the system is completely
safe to install and reduces the need for qualified electricians to complete the
wiring.
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.
† Linked internally
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. The pulse rate is also programmable, so that a pulse can, for
3
example, be programmed to occur every .001m
.
Duration of the pulse is around 10ms thus the maximum pulse output frequency
is 49Hz. Hence, in the above example, if the volumetric flow rate was 60
3
/hour, then this is equivalent to 0.0167 m3/sec. If a pulse occurs every 0.001
m
3
then the output frequency would be 16.7 Hz.
m
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.
Output characteristics for Relay 0 and Relay 1 are:
Maximum Voltage 30 Volts dc
Maximum Current 250mA dc
Off State Leakage Current 5uA maximum
On State Resistance 6 ohms maximum
The relays can be individually programmed during Set-up to alarm on:
Flow rate Low or High
Power Low or High
Feed Temperature Low or High
Return Temperature Low or High
Temperature Difference Low or High
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: 2.0mA to 22.0mA.
Linearity & Resolution: 0.02% of span.
Accuracy: 0.1% of span.
Response Time: 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. However,
ensure that the front panel is aligned at both connector points before tightening
the screws.
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 and must be connected to a good earth,
using a multi-stranded, braided wire.
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.
In order to comply with the requirements for Electromagnetic Compatibility as
per EMC Directive 89/336/EEC of the Council of the European Community, this
wiring practice is mandatory.
Although it is possible to connect shields to the (-) volt supply terminal (51 -),
this practice is not in accordance with the EMC Directive.
68 Installation
Termination Board
Installation 69
7.6 TERMINAL DESIGNATIONS
Terminal numbering is in accordance with international standards.
Terminal Description
1 + Feed line RTD0 Current (+)
2 - Feed line RTD0 Current (-)
3 + Return line RTD1 Current (+)
4 - Return line RTD1 Current (-)
5 + Feed line RTD0 Input (+)
6 - Feed line RTD0 Input (-)
7 + Return line RTD1 Input (+)
8 - Return line RTD1 Input (-)
10 Flow Signal Input
11 Flow Signal Reference
16 + Pulse Output (+)
17 - Pulse Output (-)
24 Meter-bus or RS485 (-)
25 Meter-bus or RS485 (+)
50 + 12 Volts Supply (+)
51 - 12 Volts Supply (-)
52 + Relay 0 (+) dc Voltage Only or 4-20mA (+)
53 - Relay 0 (-) dc Voltage Only or 4-20mA (-)
54 + Relay 1 (+) dc Voltage Only
55 - Relay 1 (-) dc Voltage Only
58 Shields
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
Heating, 27
Heating/Cooling
Mode, 27
High Alarms, 20
I
IEC 870-5, 32
IEC751, 7
Infra-red
Communication, 34
Input Connections, 50
Installation, 61
K
K-factor, 19
K-factor Range, 8
kBTU, 6
Key Switches, 12
L
Language, 19
Lead Lengths, 53
Links, 50
Location, 20
Logging, 30
Low Alarms, 20
M
M-bus
(refer Meter-bus), 32
Mains Powered, 54
Meter-bus, 32
Metric, 19
Modbus RTU, 35
Model Number, 5
Mounting, 61
N
Namur Switch, 52
O
Off-Peak and Peak, 29
Offset Function, 20, 26
OIML, 3
Operating Modes, 27
Operating Time, 15
Operation, 11
Opto-Sensors, 52
Output Connections, 50
P
Panel Mount, 63
Parity, 21
Peak and Off-Peak, 29
Peak Power, 14
Platinum, 53
Power, 3
Power Adapter, 54
Power Requirements, 8
Power Supply, 54
Pressures, 3
Protocol, 32
Pulse Inputs, 50
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
Index 71
W
Wall Mounting, 61
Wiring Practices, 67
Z
Zero, 26
T
Temperature
Difference, 7
Temperature Range, 7
Terminal
Designations, 69
Termination Board, 68
Ton, 6
U
Units of
Measurement, 24
V
Verification Seal, 66
Loading...