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User manual
CF8-W-Disp-AL
CO2 transmitter with two relays prepared for
Modbus communication protocol
General
The IAQ-sensor product CF8-W-Disp-AL is used to measure indoor air carbon
dioxide concentration in rooms. It is flexible controller with programmable output for
relay control of e.g. mixed air dampers, humidifier and fans. The measured values
are shown on the display. The sensor is designed for wall mounting.
The unit is designed for connecting to Direct Digital Control (DDC). The linear output
functions are pre-programmed as CO2 transmitters with jumper selected outputs. The
measuring ranges can be modified from a PC (Windows) and use of the software UIP
(version 4.3 or higher) together with the RS232 communication cable.
Figure 1 CF8-W-Disp-AL for wall mounting
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Functional description
This part describes the function of the standard configuration of CF8-W-Disp-AL. It
may be re-programmed before or after the installation by a PC and the standard UIP
software (version 4.3 or higher).
Out(1) = measuring signal of carbon dioxide concentration 0-4 % CO2
Out(2) = measuring signal of carbon dioxide concentration 0-4 % CO2
OUT3 = ON/OFF signal of demand of air quality
OUT4 = ON/OFF signal of demand of air quality
The opening of the relay is controlled by the hysteresis of the relay. See figure 4.
Figure 2 The measuring signal of carbon dioxide.
Figure 3 The measuring signal of carbon dioxide
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Output
sensor
sensor
Configuration
Output Range
Formula for calculation
a-b c–d
Value = (reading-a)/(b-a)*(d-c)+c
a = lowest value of the configuration
d = highest value of the range
Terminal Default
OUT1
OUT2
Relay 1
0-20 mA
4-20 mA
Closed
Open
Relay 2
Closed
Open
Default Output
Range
0-4 % CO2
0-4 % CO2
> 1,5 % CO
2
< 1,4 % CO
> 3,0 % CO
2
2
< 2,9 % CO
2
Outputs of this
Table I. Default output configurations for CF8-W-Disp-AL
Formulas for calculati on of out put values
Output Range of this
0-10 VDC
2-10 VDC
4-20 mA
0-4 % CO
0-4 % CO
0-4 % CO
2
2
2
CO2 value = Volt/10*4
CO2 value = (Volt –2)/8*4
CO2 value = (mA-4)*4/16
b = highest value of the configuration
c = lowest value of the range
Table II. Calculation of CO2 value for CF8-W-Disp-AL
Output Configurations
If other options are needed for the application, the output jumpers have to be
configured before the unit is powered up. Each jumper selection is independent from
the others, except for the “Start point selection” jumper, which affects both, Out(1) &
Out(2), linear outputs. Alternative measuring ranges of the outputs can be selected
with the software UIP (version 4.3 or later).
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n
Out(2) (4-20mA or 2-10V).
jumper
Out(1).
Out(2).
Jumper Positio
Start
point
selection
jumper
Communi
-cation
selection
Out(1)
Out(2)
0%
20%
MB
SA
Current
Voltage
Current
Voltage
Function
Jumper top position provides 0Vdc or 0mA start point for Out(1),
Out(2)
(0-20mA or 0-10V).
Jumper bottom position provides 2Vdc or 4mA start point for Out(1),
Jumper at top position provides Modbus communication protocol
Jumper at bottom position SenseAir communication protocol
Connection in position “Current” provides 0/4-20mA output ra nge for
Out(1).
Connection in position “Voltage” provides 0/2-10VDC output range for
Connection in position “Current” provides 0/4-20mA output ra nge for
Out(2).
Connection in position “Voltage” provides 0/2-10VDC output range for
Table II. Configuration jumpers for CF8-W-Disp-AL
FUNCTIONAL TEST of CO2 Sensor CF8-W-Disp-AL
The unit has three LED’s – one yellow and two red – to indicate the status of the
controller.
Yellow LED - ”Call for maintenance” is lit, if an error flag is set or the measurement is
out of range. This information is also shown on the display by the wrench icon.
Left red LED - ”the relay1 is actuated” is lit, when Out(3) (relay1) is actuated (closed).
Right red LED - ”the relay2 is actuated” is lit, when Out(4) (relay2) is actuated
(closed).
A simple and visual functional test can easily be performed. Take a breath and blow
the air from a distance of a few centimetres on the sensor. The sensor will detect a
rapid increase in the carbon dioxide concentration. The red LEDs are lit when the
CO2 concentration passes the pre-set values.
Self-diagnostics
The system contains complete self-diagnostic procedures. A full system test is
executed automatically every time the power is turned on. In addition, constantly
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during operation, the sensor probes are checked against failure by checking the valid
dynamic measurement ranges. All EEPROM updates, initiated by the sensor itself, as
well as by external connections, are checked by subsequent memory read back and
data comparisons. These different system checks return error bytes to the system
RAM. The error codes are available by connecting a PC with a special RS232 cable
connected to the UART port slide connector. The error codes are shown in the
software UIP (version 4.3 or later). Warm up and Out of Range are the only bits that
are reset automatically after return to normal state. All other error bits have to be
reset manually after return to normal by power off/on.
The yellow LED flashes if an error has been detected. If a fatal error has been
detected the yellow LED is lit.
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Bit #
Error
code
Error description
Suggested action
0
N/A
Fatal Error
Try to restart sensor by power
OFF/ON. Contact local distributor
1
2
Reserved
2
4
Algorithm Error.
Try to restart sensor by power
Contact local distributor.
3
8
Output Error
Check connections and loads of
higher.
4
16
Self-Diagnostic Error.
replacement.
Check detailed self-diagnostic status
Contact local distributor
5
32
Out of Range Error
Try sensor in fresh air.
6
64
Memory Error
operations.
Check detailed settings and
version 4.3 and higher.
7
128
Warm Up state
restart sequence.
If it doesn’t disappear in half a
Error code and action plan
Indicate wrong EEPROM
configuration.
Detected errors during output
signals calculation and
generation.
May indicate the need of zero
calibration or sensor
Accompanies most of other
errors. Can also indicate
overload or failures of sens or s
and inputs.
Resets automatically after
source of error disappearance.
OFF/ON.
Check detailed settings and
configuration with UIP software
version 4.3 and higher.
outputs.
Check detailed status of outputs
with UIP software version 4.3 and
with UIP software version 4.3 and
higher.
Check detailed status of
measurements with UIP software
version 4.3 and higher.
See Note 1!
Non-fatal error during memory
Is always set after power up or
power failure. Resets after
Note 1. Any probe is out of range. Occurs, for instance, during over exposure of CO
sensor, in which case the error code will automatically reset w hen the measurement values
return to normal. Could also indicate the need of zero point calibration.
Remark: If several errors are detecte d at the same time the different error code numbers will be
added together into one single error code!
PLEASE NOTE! The sensor accuracy is defined at continuous operation (at
least 3 weeks after installatio n )
configuration with UIP software
minute, check power stability.
2
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Gas inlet
Gas inlet
Maintenance
The CF8-W-Disp-AL is basically maintenance free. An internal self-adjusting
calibration function takes care of normal long term drift associated to the CO2 sensor.
To secure the highest accuracy, a time interval of five years is recommended
between CO2 calibrations, unless some special situations have occurred. A zero
calibration can be performed by use of pure nitrogen or air that has passed through a
chemical absorber and a PC together with the UIP software version 4.3 (or higher).
The Zero Calibration Bag can be used to produce carbon dioxide free air. The
software can be free downloaded from www.rotronic.com. The RS232-cable and the
zero calibration bag can be ordered from Rotronic. The cable is to be connected to
the UART port slide connector. For change of control parameters and re-calibration
of CO2 this PC tool has to be used. The check can be done on site without interfering
with the ventilation system.
This is for sensors with measuring ranges between 0-3000 ppm and 0-4%:
When a zero calibration shall be executed a plastic tube with 2.2 mm outer diameter
and 0,8 mm inner diameter shall be inserted in marked holes of the sensor. Plastic
tubing is connected to the tube. The gas flow should be between 0.3 and 1.0 l/min.
Figure 4 Part of the PCB with holes for gas inlets marked.
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~
+
Figure 5 The CF8-W-Disp-AL printed circuit board with the terminal area enlarged at right.
The darker positions are default settings. Communication protocol is set with communication jumper
Upper position Modbus communication protocol
This product is in accordance with the EMC 2004/108/EC, 92/ 31/EEG including
amendments by the CE-marking Directive 93/68/EEC
The product fulfils the following demands:
EN 61000-4-2 level 2, EN 61000-4-3 level 2,
EN 61000-4-4 level 4, EN 61000-4-6, EN 61000-4-8 level 4, EN 55022 class B
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