Fault Reaction Function; Hardware Settings - ABB Q957 User Manual

Step Operation
4 The user cannot start the motor while the drive STO is active.
5 Normal operation resumes after the user:
• sets the POUS switch [S] to the closed position
• resets the drive (if the drive tripped on a fault)
• makes sure that the drive receives the start signal (depends on the configuration, see the firmware
manual).

Fault reaction function

Definition: A safety function requires a "fault reaction function" that tries to initiate a safe
state if it detects a failure in the safety system.
The fault reaction function of the POUS safety relay trips the system, if it detects a failure
in the safety circuit (for example, short circuit between signals, open circuit, or redundancy
fault).
If a fault is detected, the fault reaction function:
• activates the POUS request
• activates the drive STO function
• keeps the safe state activated and the POUS indication lamp on until the fault is repaired
and the safety function is reset.
The STO function has its own internal fault diagnostics and fault reaction function.

Hardware settings

The hardware settings for the safety function are set at the factory.
The settings in the POUS safety relay [A65] are:
• Cross fault detection is set to With
• Start mode is set to Automatic.
Note: If the cross fault detection is set to Without, the fault diagnostics of the wiring
decreases.
For more information, see the circuit diagrams delivered with the drive.
Option description 17