INSTALLATION AND OPERATING INSTRUCTIONS
SKF Multilog On-line System IMx-8/IMx-8Plus
30 (63)
SKF Multilog On-line System IMx-8/IMx-8Plus
User Manual
Revision E
2.5.11 Connecting relays
The IMx-8/IMx-8Plus each have three relay driver outputs that can be used for
remote indication of System status, Warning (Alert) and Alarm (Danger), conditions.
The output terminals for these are situated on the bottom end cap of the IMx, refer
section
. The general arrangement for connecting a relay is shown below,
Figure 16
Connecting a relay to the Status, RS, relay driver output
For each relay driver output, a relay coil can be connected across the relevant 24V
and R’x’ terminals.
These R’x’ terminals RS, R1 and R2 are low side d
rivers known
as open collectors
and when energised they ‘complete the circuit’ and p
ower the coil.
The IMx-8/IMx-8Plus relay driver outputs make ava24 V DC power for this
purpose up to a maximum current of 70 mA, shared across all relays connected.
Ensure then, that any relays used have a coil resistance compatible with the
minimums indicated below:
Table 4
Minimum relay coil resistances depend on the number of relay drivers in use
No. relays
Minimum coil resistance for 70 mA maximum demand
1
345
Ω
2
690
Ω
3
1 035
Ω
In operation, the system relay driver is energised only when the system status is OK,
also indicated by the red SYS led being off. The system relay driver will be de-
energised during power loss and when internal system faults have been detected:
failsafe behaviour. The output will also be de-energised in case of a sensor cable
fault or a cable fault from an external communication source, such as Modbus, if this
behaviour is enabled in the system database.
Note that the system relay will ignore the Monitor connection and any time
synchronisation errors and focus on errors that could disrupt alarms or warning
detection.
The R1 and R2 outputs have a, fixed, non-failsafe behaviour, energised on alarm.
