Kinetix 6000 Motor losing position

[wes.s]

I've been struggling with this for a while. I finally had time to play with it.

I've probably replaced every servo motor in this machine at one time and it never was a problem. A while back one axis would lose position when powered down.

Today I noticed that when you power it up, it shows a number fairly close to the one I used to set position. It doesn't matter where I leave the axis at when I power it down.

I've read the thread at http://www.plctalk.net/qanda/archive/index.php/t-68828.html

I really didn't see anything I wasn't already doing other than using motion direct commands instead of using the logic for setting home that the builder wrote for setting position.

Finally, out of frustration I tried another motor from spares. That one keeps its position.

Amp 2094-bc01-m01 Motor MPL-B430P-M from Axis Properties.

The motor I put in is a replacement item, old one had separate brake cable (3 connectors) new one has conversion cable and a conversion y cable. MPL-B430P-MJ74AA.

The old one is a MPL-B430P-MJ24AA


From what I've read, a value is stored in the motor. What is the storage medium? Flash or something battery backed up?


I have another axis with a 560 motor that has the same forgetting problem. I'd like to know more about why this loss of position is happening. I have 5 other axes that I don't want start forgetting things.


Thanks,


Wes

 

[wes.s]

I opened up the motor I took off. It has a SICK-Stegmann SRM50-HFA0-K01 feedback device in it. Sin/Cosine, multi turn with 512 bytes of EEprom. I guess I know where the position data is stored now.


I found some info about it here:
http://static6.arrow.com/aropdfconv...ee2276008b896ece545b228bca/srm50-hfa0-k01.pdf




I'm still scratching my head, there is a 485 interface, I would hope data written to the motor would be read back.


The machine is back in production, it may be weeks until I can play with it unless it forgets its way again.


Wes


PS


Found more info on the device. https://cdn.sick.com/media/docs/5/65/865/operating_instructions_specification_hiperface%C2%AE_motor_feedback_protocol_en_im0064865.pdf