252 The Safe torque off function
Start-up including validation test
To ensure the safe operation of a safety function, validation is required. The final assembler
of the machine must validate the function by performing a validation test. The test must be
performed
• at initial start-up of the safety function
• after any changes related to the safety function (circuit boards, wiring, components,
settings, etc.)
• after any maintenance work related to the safety function
• after a drive firmware update.
Competence
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The validation test of the safety function must be carried out by a competent person with
adequate expertise and knowledge of the safety function as well as functional safety, as
required by IEC 61508-1 clause 6. The test procedures and report must be documented
and signed by this person.
Validation test reports
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Signed validation test reports must be stored in the logbook of the machine. The report shall
include documentation of start-up activities and test results, references to failure reports
and resolution of failures. Any new validation tests performed due to changes or maintenance
shall be logged into the logbook.
Validation test procedure
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After wiring the Safe torque off function, validate its operation as follows.
Note: If the drive is equipped with safety option +L536, +L537, +Q950, +Q951, +Q952,
+Q957, +Q963, +Q964, +Q978 or +Q979, also do the procedure shown in the documentation
of the option.
Action
WARNING!
Obey the safety instructions. If you ignore them, injury or death, or damage to the equipment
can occur.
Make sure that the drive can be run and stopped freely during start-up.
Stop the drive (if running), switch the input power off and isolate the drive from the power line using a
disconnector.
Check the STO circuit connections against the wiring diagram.
Close the disconnector and switch the power on.
Test the operation of the STO function when the motor is stopped.
•Give a stop command for the drive (if running) and wait until the motor shaft is at a standstill.
Make sure that the drive operates as follows:
•Open the STO circuit. The drive generates an indication if one is defined for the 'stopped' state in
parameter 31.22 (see the firmware manual).
•Give a start command to verify that the STO function blocks the drive's operation. The drive generates
a warning. The motor should not start.
•Close the STO circuit.
•Reset any active faults. Restart the drive and check that the motor runs normally.