7.17 Wire fail detection
If it is necessary to supervise the sensors/wires connected to the multi-inputs and analogue inputs, then it is
possible to enable the wire break function for each input. If the measured value on the input is outside the
normal dynamic area of the input, it will be detected as if the wire has made a short-circuit or a break. An
alarm with a configurable fail class will be activated.
Input
Wire failure area
Normal range
Wire failure area
4-20 mA
< 3 mA
4-20 mA
> 21 mA
Pt100
< 82.3 ohm
-
> 194.1 ohm
Pt1000
< 823 ohm
-
> 1941 ohm
RMI Oil, type 1
< 1.0 ohm
-
> 195.0 ohm
RMI Oil, type 2
< 1.0 ohm
-
> 195.0 ohm
RMI Temp, type 1
< 4.0 ohm
-
> 488.0 ohm
RMI Temp, type 2
< 4.0 ohm
-
> 488.0 ohm
RMI Temp, type 3
< 0.6 ohm
-
> 97.0 ohm
RMI Fuel, type 1
< 0.6 ohm
-
> 97.0 ohm
RMI Fuel, type 2
< 1.0 ohm
-
> 195.0 ohm
RMI configurable
< lowest resistance
-
> highest resistance
Level switch
Only active if the switch is open
Principle
The illustration below shows that when the wire of the input breaks, the measured value will drop to zero.
Then the alarm will occur.
Wire failure
Wire failure
Wire break
Lower failure
limit
Upper failure
limit
Input signal
(mA, °C,b, %)
t
CGC 400 DRH 4189340786 UK
Additional functions
DEIF A/S
Page 70 of 96