ICS-7-OEM Instruction Manual
02058-53-000
Page 23 of 29
Issue 3 19 January 2021
Mismatch Detection Settings
The Safety Circuit Mismatch Detection behaviour is set by the option switch on the right-hand side
of the Emergency Stop input terminals. The options are described below.
Option
On
Off
1
Mismatch fault is automatically reset on
cycling the 24V power. Power must be
turned off for at least 10 seconds.
Mismatch fault must be reset by pressing
the Fault Reset button or by a momentary
contact closure at the Fault Reset input
2
Mismatch detection is disabled, for use
with single-channel systems
Mismatch detection works normally
3
Mismatch detection on the Output
Monitor input is disabled, but still
operates on safety circuits
Mismatch detection works on safety
circuits and the Output Monitor input
Pre-check Mismatch Detection and Safety Logic Plus
Safety relays used on expansion cards are also monitored for mismatch, so should any of these
relays become stuck a mismatch is signalled. The Safety Logic Plus interface card generates a
mismatch event during its start-up sequence, so if this expansion card is being used the pre-check
mismatch detection must be disabled by setting Option 3 to On. Mismatch detection of the safety
circuits is still provided in this mode.
8.2 Clearing a Mismatch Fault Indication
In all cases the fact that a mismatch fault has been indicated warns users that the safety of the
system may be compromised. Site-specific instructions should indicate the actions to be taken by
users in such an event.
If the auto reset option has been selected, the system may be temporarily cleared by turning the
power supply off, waiting for ten seconds, then turning it back on again. In this case the system
should be attended to by a suitably qualified technician to identify and repair the fault at the earliest
opportunity as a fault has been identified and the system may cease to provide protection without
further warning.
If the ICS-7-OEM has been configured to permanently lock out, it can only be reset by pressing the
Fault Reset button. This should only be undertaken by suitably qualified technicians once the fault
has been identified and repaired as otherwise the unit will just lock out again.
