GasCheck
Operating Manual V2.4
5
NOTE
Never operate the sensor without a filter. If the sensor is
used without a filter, it will function initially but the
optics will gradually become contaminated leading to
drift in the readings and premature failure of the sensor.
The sensor is capable of operating with up to 100 %RH without ill effect
provided that the conditions are non-condensing. If there is any possibility that
condensing conditions might occur, the sensor should be protected by a water
trap.
If an outlet pipe is connected to the sensor, care should be taken to ensure this
does not create a back-pressure in the cell which would lead to erroneous
readings (see Section 4.2). The outlet should be free venting via tubing, which
is neither too narrow nor too long. It is not advisable to connect the outlet to
other sensors or components, which might restrict the flow.
3.3
Electrical connection for GasCheck
The sensor head requires only a +15 V supply (connected to both the source
board and the detector board) and provides a 0 to 1 V output, offset from the 0
V rail by 5 V (the +5 V rail is also provided as a reference output voltage)
PL1 on
the
detector
board
PL1 on
the
source
board
5
1
1
2
Figure 3.4
Location of the PL1 connectors
Source PCB, PL1
Detector PCB, PL1
pin 1: +15 V
pin 1: +15 V
pin 2: ground
pin 2: ground
pin 3: 0 to 1 V output
pin 4: +5 V offset
