14
G
Installation and Commissioning
Automatic calibration of the VOC measurement (permanently active)
The regular exchange of fresh air is all that is required for the self-calibration technology in the sensor. The device detects this condition and
performs the calibration automatically. It is sufficient to open the windows or set the air conditioning system to use outdoor air at regular intervals.
Make sure that no harmful substances influence the ambient air during this process. Proceed as follows:
Open all windows fully or set the air conditioning system to use outdoor air 1x weekly for 15-20 minutes. During this time, the release of gases
from volatile organic substances must be prevented as far as possible.
Regular ventilation of the rooms and flushing of the duct with fresh air will increase the measuring accuracy of the sensor.
Every time the device is switched on, the automatic calibration cycle restarts and calculates a correction value across the operating period.
In case of power disruptions of less than 7 days, the calculation algorithm may be supported with a manual calibration to adjust the correction
value more quickly..
Manual calibration of the VOC measurement
Manual calibration can be carried out independently of automatic calibration. Sufficient fresh air must be
provided before and during the calibration procedure. Also make sure that no harmful substances influence
the ambient air. Proceed as follows to perform manual calibration:
1.
Preparation: Prevent the release of gases from volatile organic substances as far as possible,
open windows and set air conditioning system to use outdoor air, remove the housing cover and wait
15 minutes.
2.
Press and hold the
“ZERO VOC”
button until the flashing LED row changes to a steady light after
5 seconds. Devices with a display indicate
“AUTO 0”
and change the countdown from 5 to 60. The calibration process has started.
Keep the windows open or
the air conditioning system set to use outdoor air.
3.
After 60 seconds, the calibration is complete (status LED has gone out, the countdown is complete)
and the device indicates or transmits the current VOC concentration.
Switching point setting
A potential-free changeover contact is available as a switch output.
A switching point between 10 % and 95 % of the measuring range can be selected using
the SET potentiometer. The 10 % value is added to the fresh air limit of 400 ppm for CO2.
(600...1900 ppm with MR = 0...2000 ppm or 900...4700 ppm with MR = 0...5000 ppm).
With other measurands, the corresponding lower limit is used directly as a basis.
(VOC: 10...95 %, Temperature: +5...+48 °C, Humidity: 10...95% r.H.)
The assignment of the switch output to measurand is done via DIP switch (DIP 7 and DIP 8).
Offset
Each measuring channel has a separate offset potentiometer for subsequent adjustment of the measurement.
The adjusting range is ± 10 % of the measuring range.
Display
In the first line, the
measurements
with the corresponding
units
( CO2 in
ppm
, VOC in
%
, temperature in
°C
, relative humidity in
% r.H.
)
are displayed in a cyclical series.
In the second line, the
switching status of the relay
is shown on the left as a circuit
(full
●
= relay energised; empty
○
= relay de-energised)
followed by the corresponding
indicator
(
C
for CO2;
V
for VOC;
T
for temperature;
H
for relative humidity in
% r.H.
)
and the
switchpoint value
is shown on the right.
