6.39 Input function selection
Digital input alarms can be configured with a possibility to select when the alarms are to be activated. The possible selections of the
input function are normally open or normally closed.
The drawing below illustrates a digital input used as an alarm input:
1. Digital input alarm configured to NC, normally closed. This will initiate an alarm when the signal on the digital input disappears.
2. Digital input alarm configured to NO, normally open. This will initiate an alarm when the signal on the digital input appears.
INFO
The relay output function can be selected to be ND (Normally Deenergised), NE (Normally Energised), Limit or Horn.
Dig in
Multi-line 2
Com
+ V DC
Alarm
input
Relay out
6.40 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 < 3mA 4-20 mA > 21 mA
0-40V DC ≤ 0V DC - N/A
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
P100 < 82.3 ohm - > 194.1 ohm
P1000 < 823 ohm - > 1941 ohm
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.
DESIGNER'S HANDBOOK 4189341275A EN Page 165 of 196
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