PFLX 753 difference between safety and hardware enable?

I just got lots of help with my original problem with PFLX753. But in the process, I found another question and I thought it'd be more appropriate to post a new thread.

At my work, a safety relay output is wired to the drive's STO enable input, and this is a safety enable option.

Why don't I simpy go with hardware enable and not buy the STO module? I can just wire the safety relay output to the DI0.

If I have to guess, with the safety enable option I have more flexibility on how to configure the enable?

The hardware and implementation of the STO card has gone through specific design and testing to define its reliability for safety operation. The hardware enable input has not.

Keith

kamenges said:

The hardware and implementation of the STO card has gone through specific design and testing to define its reliability for safety operation. The hardware enable input has not.

Keith

Click to expand...

So safety enable is more reliable than the hardware enable? If so, is it industry trade knowledge or actually a claim by AB?

From reading other forums, it sounds like the STO takes care of motor decel issues after powered off. Makes sense. STO will give more "controlled" stop. If anyone knows any other benefit of the STO module over simple hardware enable, please let me know. Thanks.

It is all to do with safety

My understanding is
The STO Card has gone through a design process the ensures that the drive outputs are in a "safe state" if the safety enable input is not enabled, especially in a failure mode (read internal components letting the smoke out)
The hardware enable has NOT gone through that same process. The final effect may be the same (drive outputs will not operate) however there may be safety issues that may crop up in certain failure situations.