Multiple PF525 sto wiring ?

[jdolecki 0]

I have three PF525 I need to wire the STO pins.

Is  it acceptable to wire all them in parallel to the safety relay out.

Or does each drive need its own relay output?

Thanks

 

 

[pturmel 167]

2 minutes ago, jdolecki said:

wire all them in parallel

IIRC, this will function, but reduces the safety classification in most cases.  If the upstream relay is physically two separate relays in series internally, with appropriate failure interlocking, it may be acceptable.  If the upstream safety relay provides paired solid-state outputs, parallel connection would almost certainly not be acceptable.

Without a risk assessment, I wouldn't do it.

[jdolecki 0]

The risk assessment say all motion must stop if e stop is pushed.

My Kinetex5100  servo manual shows the safety inputs in series for multiple drive to STO so I assumed this was the same for the PF.
 

So I  assumed this was acceptable for the PF 525 but they would have to be paralleled.

what do I know

[jdolecki 0]

Found this in 520 drives manual

[pturmel 167]

Yeah, somehow I missed the multiple PF525 situation.  I thought you wanted to feed S1 and S2 on one PF525 from a single circuit. But this:

6 hours ago, jdolecki said:

The risk assessment say all motion must stop if e stop is pushed.

Is a very simplistic risk assessment.  It doesn't address the level of faults that must be accepted with still-working safety stop.

[BobLfoot 303]

The manufacturer documentation you show is very clearly labelled "Coast with TWO Powerflex drives".  I would not assume it can be applied to THREE without checking with Rockwell Technical Experts.  There is the possibility that the Relay Output cannot support more than two drive input units.  If there is a "coast with MULTIPLE Pwoerflex Drives" example then I would be much more comfortable with doing what you're asking from a single relay.

[VFD Guy 16]

11 hours ago, BobLfoot said:

The manufacturer documentation you show is very clearly labelled "Coast with TWO Powerflex drives".  I would not assume it can be applied to THREE without checking with Rockwell Technical Experts.  There is the possibility that the Relay Output cannot support more than two drive input units.  If there is a "coast with MULTIPLE Pwoerflex Drives" example then I would be much more comfortable with doing what you're asking from a single relay.

Looks to be a cascade configuration. I wouldn’t focus on 2 vs multiple 

[BobLfoot 303]

18 hours ago, VFD Guy said:

Looks to be a cascade configuration. I wouldn’t focus on 2 vs multiple 

yes and each drive draws 6ma.