External Device Monitoring Function - Omron F3SJ-A series User Manual

System Configuration and Functions

External Device Monitoring Function

This function detects malfunctions, such as welding, in external relays (or contactors) that control the
hazardous zone of a machine.
This function constantly monitors that a specified voltage is applied to the receiver's external device
monitoring input line, and enters lockout state when an error occurs. The relay's operational delay can
be up to 0.3s without being evaluated as an error.
For example, if the (N.C.) contact is not closed and a specified voltage is not applied to the external
device monitoring line within 0.3s after the safety outputs turn from ON to OFF, it is evaluated as an
error and enters a lockout state.
To utilize this function properly, use safety relays and contactors that have forcibly guided or
mechanically linked contact structure.
Wiring
Perform wiring so that 9 to 24V is applied to the external device monitoring line via the external relay's
normally closed (N.C.) contact.
When external device monitoring function is not being used, apply auxiliary output 1 to the external
device monitoring input.
- Wiring when external device monitoring function is used p.19
- Wiring when external device monitoring function is not used p.20
Timing Chart
The F3SJ reads out a device monitoring input value 0.5s or later after the power of the F3SJ is turned
ON. If the status of the safety outputs is changed back to the original status within the allowable delay
time, the F3SJ will not enter the lockout state.
Unblocked
/Blocked
Safety output
External device
monitoring input
T1: Allowable delay time
Operation of the F3SJ's Internal Indicators When External Device Monitoring
Function is Performed
When an input is applied to the external device monitoring input, the external device monitoring
indicator turns ON.
F3SJ-A
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User's Manual
Unblocked
Blocked
ON
OFF
T1=0.3s
ON
OFF
Lockout
T1=0.3s