Grounding Of Protective Shields; Operation Principle; Start-Up Including Acceptance Test; Competence - ABB ACH580-31 Series Hardware Manual

208 The Safe torque off function
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Grounding of protective shields

• Ground the shield in the cabling between the activation switch and the control unit
at the control unit.
• Ground the shield in the cabling between two control units at one control unit only.

Operation principle

1. The Safe torque off activates (the activation switch is opened, or safety relay
contacts open).
2. The STO inputs on the drive control unit de-energize.
3. The control unit cuts off the control voltage from the output IGBTs.
4. The control program generates an indication as defined by parameter 31.22 (refer
to the firmware manual of the drive).
5. The motor coasts to a stop (if running). The drive cannot restart while the
activation switch or safety relay contacts are open. After the contacts close, a
reset may be needed (depending on the setting of parameter 31.22). A new start
command is required to start the drive.

Start-up including acceptance 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 an acceptance
test. The acceptance 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.
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Competence

The acceptance 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.
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Acceptance test reports

Signed acceptance 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 acceptance tests performed due to
changes or maintenance shall be logged into the logbook.
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Acceptance test procedure