Dräger REGARD 3900 Series Instructions For Use Manual page 14

Components
+ signal - 0 V
The input channel signals duplicate the signal outputs and 0 V but are electrically
isolated from the input channels. The signal outputs are current sources that only
work if they are connected to a passive load.
Input channel is inactive
1) The zero terminal provides a 4 mA output signal for very low gas values of ± 2% of the mea-
suring range.
Alarm lock
If the inhibit switch is moved to position 1, the output signals are frozen in their
current state.
If the inhibit switch is moved back to position 0, the output signals return to their
normal state.
Output module fault
In the event of a fault on the output module, all channels have an output signal of
1 mA (± 0.3 mA).
Input signal (mA)
Below 3.8
3.8 to 4.2
4.3
12
20
Over 20
Reading on the display
(range 0–100)
Under-range or mainte-
nance
0
2
50
100
Over-range
Display blank
Output channel signal
(mA)
As input signal
1)
4.0 (zero terminal )
4.3
12
20
As input signal
0
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REGARD 3900