SECTION EIGHT – Safety function RESTART INTERLOCK (Optional)
DS2000 USER’S MANUAL (rev.C)
8.14
8.10 EXTERNAL PLAUSIBILITY TESTS
The following tests of plausibility must be made outside of the drive (e.g. by a PLC).
• “Channel 1 verification”
The external system must monitor this output signal for plausibility with its input signal
Channel 1 (see par.8.4.1.1).
• “Channel 2 verification” (if used)
The external system must monitor this output signal for plausibility with its input signal
Channel 2 (see par.8.4.1.2).
• Monitoring by a standard Programmable Electronic System
• Minimum functional requirements
- The automatic monitoring shall, at discovered fault, disconnect the line contactor and
prevent a new start until fault has been removed
- The change of the monitoring signal shall be checked automatically:
- at the start up and
- during each stopping and starting sequence.
• Wiring requirements to avoid common mode failures
The external cable to RESTART INTERLOCK connector must be protected against
mechanical damages according to the safety requirements of EN ISO 13849-2:2003,
tab. D.4 (prEN 954-2) in order to prevent short circuits.
• Software verification
Following safety related principles, it is necessary to verify the software and give
instructions on following revisions
• Modification of software
The manufacturer shall write a warning in the software close to the part of program
concerning the safety function that this part must not be deactivated or modified for
safety reasons (see also clause 11.7.4 of EN ISO 12100-2)
• Other requirements
The output of the PLC to the line contactor shall be periodically tested by monitoring the
plausibility of the NC contact of the line contactor
• Protection of program
- The program shall be monitored by e.g. a watchdog
- The program shall be in permanent memory protected against electrical interference and
shall be equipped with a start-up test procedure
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