GasCheck
Operating Manual V2.4
7
Alternatively, connections may be made via the 9 way D-type connector PL1
that carries additional signals used during factory testing. The connections for
PL1 are:
Pin Number
Function
1
+24V Power Input
2
+Analogue Output
3
AC signal from sensor head
4
+5V rail
5
+15V rail
6
0V Power Input
7
-
Analogue Output
8
DC signal from sensor head
9
0 to 2V linear output
3.5
Power supply requirements for GasCheck
The sensor should be connected to a regulated, clean 15 V power supply. The
sensor is insensitive to the actual power supply volts and will achieve
specification for
steady
supply volts in the range 14.2 V to 15.8 V.
The load current taken by the sensor is not constant and contains significant
components at 8 Hz, 1 kHz and their harmonics. The peak current required
during normal operation is 300 mA although the average current (to be used
for power dissipation calculations) is only 60 mA. The power supply should
be capable of supplying this load whilst maintaining a clean regulated output.
The inrush current at power-up is 1.2A and the power supply should be
capable of supplying this although the supply voltage need not be maintained
at 15 V during this time.
A standard 7815 series regulator (not 78L15 version) with a 100 nF output de -
coupling capacitor and a 470 nF input de-coupling capacitor is recommended
for use with the sensor.
