IDEC HR6S Series, Original Instructions Manual, Page: 43 / 91

Engineering
HR9Z-B2190 8/2020
43
Signal Interlock Monitoring
Overview
Signal interlock is a monitoring function used to detect conditions in which one of the
sensors/devices cannot provide the expected input signal for the device, for example, as a result
of contact welding.
The device expects “simultaneous” deactivation of the two input channels of the safety-related
input within the signal interlock monitoring time of 200 ms.
If the two monitored input channels of the safety-related input are not deactivated within 200 ms,
this is a signal interlock condition and the device triggers a signal interlock alert. The device
remains in the defined safe state, i.e., there is no transition from operating state Run: Outputs
Deenergized to operating state Run: Outputs Energized (T3).
To exit the signal interlock condition, the two affected input channels of the safety-related input
must be deactivated for at least one second. After that, the input channels of the safety-related
input can be activated again which activates the safety-related output as well.
Signal interlock is available for certain of the application functions
( see page 56 ) the device
provides.
Examples
The following figure illustrates a condition without signal interlock:
Both input channels of the safety-related input are deactivated within the signal interlock
monitoring time of 200 ms. When they are activated again, the safety-related output is also
activated.
Safety-relaed input S##
Safety-relaed input S##