Many thanks for the help. I've checked the manual & you're right its parameter PD052, it needs to be set to 3 for fault indication.
I want to be able to use the machine sometimes with the VFD turned off (for probing etc.).
  • If the VFD's normally closed outputs (FA/FB) are still closed when the VFD is off I can connect these directly to my PNOZ safety relay. I should be able to check this with a multimeter.
  • Otherwise my plan is to connect FB & FC to a separate relay (something like this?) and then connect that into the E-stop circuit from the PNOZ relay. Hopefully when the VFD faults, FB + FC switch on which opens the relay and triggers the E-stop.