Oldham MX 52, Installation Manual

Page: 17 / 48

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The alarm thresholds will be selected on the basis of the gases detected and of the
corresponding standards in force.
Special case : A channel connected to a fire sensor.
-
the 100-division scale MUST be selected
-
the alarm threshold MUST have 60 divisions
(Because of the end-of-loop resistance of 2.7 kΩ, the fire sensor will deliver 4 mA when there
is no fire and 20 mA should a fire de detected).
2.3.4. The measurement facility
One minute after switching on and if no test action is performed on the keypad, the facility
scans all the live channels in succession and displays the values mesured.
Examples of the display
OR
- Each channel is interrogated for 10 seconds
- The user can interrogate a channel manually by selecting this channel with the + and – keys
for manual display lasting 1 min.
-
The user can return to normal cyclic scanning, during this minute, by pressing the + and –
keys simultaneously and the display then indicates (alternately) and 3 times in succession.
For example :
THEN
Channel 1
xx LEL CH4
Channel 2
xxx ppm CO
Channel 5
xxx ppm CO
Normal scan
xxx ppm CO