ROTRONIC CF8-W-Disp-AL User Manual

Dokument
UMA 145

Rev 3 Page
1 (8)

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

Dokument
UMA 145

Rev 3 Page
2 (8)

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

Dokument
UMA 145

Rev 3 Page
3 (8)

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).