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What can be the root cause of SAFF fault with SAF1=1 on ATV32 or ATV320?

Published date: 10 June 2020

SAFF fault on ATV32 or ATV320 drives

Product Line:
ATV32 or ATV320

SAFF fault 

 The SAFF could have a lot of root causes. Here are some examples in the attached file
In the customer SoMove file we can see that the SAF1 = 1 (bit 0 = 1).
This is the same for all SAFF registered with the safety diagnostic tool.
This bit correspond the the PWRM consistency .
SAF1 bit 0 = 1 means PWRM consistency fault.
With SAF1 bit 0 = 1, we could be in a case of instability or the Pulse on STO.
To describe how it’s works:
Even if physically you only have 1 wire connected to the STO, the Application processor gets 2 “STO values”:
- The physical signal STO
- The feedback state of the STO input read by the Motor Control
For its safety functionality the Application processor compares both. If the drive detects inconsistency between the both signals, you will have SAFF fault with SAF1 bit 0 = 1.
So like I explained before, you can have this type of SAFF related to the signal quality send on STO
For example if you have instability (or rebound): see here pulse which can generate SAFF fault (with SAF1 = 1). Blue are the pulse on STO and Red is the detection of SAFF.

So the first point on the installation will be to check with oscilloscope the STO signal (when you have the SAFF fault trip).
If you do not see any instability the issue come via another channel.
It could also occur, if some internal connection (between application and motor control) are on the limit or badly connected. In this case you will have this type of SAFF bit 0 = 1.
--> The point to check here will be this connector

It can also occur if a component is damage on the SAFE channel (this is also internal).
                --> For this product expertise will be mandatory
To resume, there are several steps for deeper investigations:
•    Check the STO signal with oscilloscope
•    If the signals are good, check the internal connection between the control block and the Power part.
•    Then have a look on the Pin bent. I think that this is not link in your case, but it’s easy to check visually.
•    Then if all seem OK, it’s better to send us back product for expertise (TEX) in order to check internally the drive connection and component.

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