Dräger SE Ex HT M, Instructions For Use Manual, Page: 43 / 60

43
Start-Up
Start-Up
Inhibiting the Alarms
Central Controller Polytron SE Ex:
It may be necessary to keep the alarm relays non-influenced when performing tests
and adjustment work.
1,2 Connect sockets on channel module with wire jumper. The relays for the 1st and
2nd alarm keep being energized even at alarm conditions.
3,4 Connect sockets on acknowledgement module with wire jumper. The relay for
audible warning keeps being de-energized even at alarm conditions.
Important Remark:
With an alarm inhibiting like this there is no electrical signal generated which
signals the alarm inhibit.
Not to leave the gas detection system in this unsafe state, organisational
measures have to be kept.
Central Controller REGARD Ex:
— Please refer to the Instructions for Use REGARD Ex.
Setting the Sensor Current
Central Controller Polytron SE Ex:
For the detection of methane the sensor current must be 270 mA.
For many other substances (see page 50) the sensing heads Polytron SE Ex PR M
and SE Ex HT M shall preferably be operated with 240 mA. If however also sub-
stances are to be detected for which a sensor current of 240 mA is not suitable, then
the sensor current must be adjusted to 270 mA.
1,2 Connect voltmeter (R
i
≥
1 M
Ω
) to the sockets.
3 Depending on the sensor used, adjust the potentiometer so that the voltmeter dis-
plays the following voltages:
Example:
The sensing head Polytron SE Ex HT M for the detection of n-Hexane needs to be
adjusted to 240 mA: Turn Potentiometer 3 such that the voltmeter reads 528 mV.
●
Let equipment warm up for 10 minutes in this condition (sensor warm-up time).
Sensing Head Polytron ... 240 mA 270 mA 276 mA
SE Ex PR M 528 mV 594 mV – – –
SE Ex HT M 528 mV 594 mV – – –
SE Ex LC M – – – – – – 607 mV
1
2
3
4
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00
7
2
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7_06.eps
1
2
3
mV
=