V90 Error on Tech Object after power off

Hi everyone,

I have an issue with my technological objects linked to V90.

The whole system is running well (PLC, servos, async motors, ...), but sometime a bug occurs. After a power off and a restart (but not only, it seems to happen also after a night at "rest"), V90 are rotating servos much faster than expected. This leads to these errors at the Tech Object level:

- Following Error

- Adaptation Error (Parameter does not exist, value unreadable or invalid. Encoder revolutions, Encoder : 1)

Those errors doesn't occurs together. It is either one, or the other. I didn't notice both at the same time.

Once I have this issue, I can't control the servos with my PLC anymore (1515F). If i clear the error, the issue remains. The error always come back as soon as I want to use the drive, by my regular commands or by the Tech Object comissionning tool. Same behaviour.

If I go online with PLC, there are no mismatch between offline/online parameters or programs. Tech object is similar offline/online.

If I go directly online with V90, there are no error within the drive itself. I can control it normally with the comissioning tool of the drive.

The only way to restore the situation is to download software to PLC (all) again. MRES or restart doesn't change anything. Downloading Tech Object only doesn't work.

So the issue is clearly on the PLC side, but I can't find anything on documentation or on forum about this issue.

Does anybody have an idea on the root cause of this issue? It doesn't occur often but it is not allowable for production.

Many thanks in advance !!

Hi,

I guess you have selected the "automatic read out" function for the encoder data exchange at the Technology Object configuration. Due to the fault with "adaption…" I think there is a fault when the PLC tries to read out the encoder data. And due to false encoder data (increments per revolution) the axis goes to fast.
So I recommend to enter the encoder data manually. How to set the data for the different types of V90 encoders is explained quickly here in this FAQ:

https://support.industry.siemens.com/cs/ww/en/view/109747183

This should help

Indeed, that's what I have done. Thank you for your advise, I will try it tomorrow !

Best regards,

Jim