Control Schematic Advice

[EddyCurrent]

Well that depends doesn't it.? . . . . It's normal for me.!!

I often put control panels on the front of the machines and having this cut power to relay is a bit of safety so the relay can't power up when changing tools etc. 24V is Safer than running high voltage into machine and messing around turning main cabinet supply off.

I'm not going there, do what you want, what I'll say is, it's not normal for the numerous industrial installations I've seen. 'Isolation and immobilisation' is a subject in itself.

Hi Eddy,
3 & 4. Now this is getting a bit deep for me, but if I am reading the Pilz documentation correct the safety contacts can handle 240VAC and 8 amps, but I stand to be corrected.
Thanks for your help
Jim

If the PILZ document says that and the VFD and PSU take less current then it sounds fine, the only issue I'd think about is the inductance of the 70v PSU transformer when the contacts open. This is why I used a separate contactor because it's cheaper to replace a worn out contactor than it is to replace the PILZ relay. Having said that I've just looked at your drawing and I can see the load is split over 4 separate contacts in the PILZ (2 in series then those in parallel with another 2 in series) so that might be okay provided they all open at the same time otherwise the first one to open gets to break the arc.