Operation - Helios KWL-VOC eC Installation And Operating Instructions Manual

Installation and operating instructions
EN
CHAPTER 4

OPERATION

Room sensor KWL-VOC eC
3.3 Connection of KWL compact units to the easyControls 3.0 control system
– Connection according to wiring diagram SS-1409. When connecting to a unit, observe
its wiring diagram, see the Installation and Operating Instructions.
Addressing
If multiple mixed gas sensors KWL-VOC eC are connected, the addressing must be ad-
justed. There must be no double address allocations for sensors! (see DIP switch table;
wiring diagram SS-1409).
The gas inter-exchange in the sensor element happens by diffusion. Depending on
the changes to the concentration and the flow velocity of the air surrounding the
sensor, the reaction of the device to the change of concentration may take place
with a delay. It is essential to choose an installation location for the device in which
the air stream flows around the sensor. Otherwise the gas exchange may be con-
siderably delayed or prevented.
4.1 General information on air quality
There is no universally uniform standard, which could be applied to a VOC sensor
(Volatile Organic Compounds). The monitored air contains a large number of sub-
stances to which the sensor responds, and gas mixtures are adjusted. Therefore
this sensor does not act selectively, but rather reflects the overall air quality. In
principle, one also cannot state precisely what is "bad air" or what is "good air"
because this is a purely subjective sensation.
4.2 Automatic air quality calibration (permanently active)
We recommend to rinse the sensor every 7 days for 20 minutes or longer with fresh
air as a basis for automatic calibration. Within a period of approx. 3 weeks, the
minimum output value for air quality is saved. During this period, the output signal is
standardised to the zero point. The maximum correction per interval is limited here.
Long-term drifts and the operation-related ageing of the sensor element are thus
completely eliminated.
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 disrup-
tions of less than 7 days, the calculation algorithm may be supported with a man-
ual calibration to adjust the correction value more quickly.
4.3 Manual calibration of air quality
Sufficient fresh air must be provided before and after the calibration procedure!
We recommend a fresh air supply of at least two hours before starting manual
calibration.
The calibration procedure is started by pressing the "ZERO" button (for approx.
five seconds). This is signalled via the flashing LED.
Then calibration takes place. During this phase, the LED is continuously active
and a 60 second countdown runs.
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