Operation Principle; Start-Up Including Acceptance Test; Authorized Person; Acceptance Test Reports - ABB ACS880-07 Hardware Manual

218 Safe torque off function

Operation principle

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

Start-up including acceptance test

To ensure safe operation of the Safe torque off 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.

Authorized person


The acceptance test of the safety function must be carried out by an authorized person
with expertise and knowledge of the safety function. The test must be documented and
signed by the authorized person.

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.

Acceptance test procedure


After wiring the Safe torque off function, validate its operation as follows. Setting of the
control program parameters is not needed. If an FSO-xx safety functions module is
installed, refer to its documentation.
Action
WARNING! Follow the
physical injury or death, or damage to the equipment.
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 by a
disconnector.
Check the Safe torque off (STO) circuit connections against the circuit diagram.
Close the disconnector and switch the power on.
Safety instructions, page 13. Ignoring the instructions can cause