User`s manual

APPENDIX C – RESTART INTERLOCK CIRCUITS C-14
CDS7324 (FORMERLY LSF-0819)
Rev. A INSTALLATION & USER’S MANUAL
C.9 EXTERNAL CONSISTENCY CHECKS
The following consistency checks must be made outside of the drive (e.g. by a PLC).
• “Channel 1 verification”
The external system must monitor this output signal for consistency with its input signal
Channel 1 (C.4.1.1).
• “Channel 2 verification” (if used)
The external system must monitor this output signal for consistency with its input signal
Channel 2 (C.4.1.2).
• Monitoring by a standard Programmable Electronic System
• Minimum functional requirements
The automatic monitoring shall, on discovering a fault, disconnect the line contactor and
prevent a new start until the fault has been removed
The transition of the monitoring signal shall be checked automatically:
- At 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 damage 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 3.7.7 of EN 292-2)
• Other requirements
The output of the PLC to the line contactor shall be periodically tested by monitoring the
consistency 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.