Motoman K6SB Retrofit

08 Aug 2021 04:36 #217175 by cakeslob
Replied by cakeslob on topic Motoman K6SB Retrofit
Ok, like I said, my controller is one model newer, but they will be pretty close. The encoders plug into the servo amp, but then they connect to the motion control card from the servo amp. Yaskawa is really good when it comes to manual dissemination, the uploaded all their manuals, and digitized some older ones. Yours is CACR-HR

It describes/defines the different control methods and motor information . The serial comunication looks different to what mechatrolink is, it looks some kind of rs422, its all defined in the manual.

The encoders appear to be similar to mine, which as far as i can tell, output abz differential singals and because their 12 bit absolute encoders, a serial channel.
This might be relevant to your encoder serial information

Gear ratios, your gears are the same as mine, so ill see what i can do about that,
in the mean time you can cross reference the part numbers in the manual to what ever you can find on google/ebay for information

I dont know that the controller parameters will yield any useful information or anything relevant to linuxcnc, and many parameters are intentionally left unlabled. it will take some time to dig through parameter manuals
The following user(s) said Thank You: phasefreq

Please Log in or Create an account to join the conversation.

20 Jan 2022 22:28 - 20 Jan 2022 22:33 #232558 by phasefreq
Replied by phasefreq on topic Motoman K6SB Retrofit
Holy crap! @cakeslob this is exactly the info I needed, thanks a ton!

So it looks like (a) my encoders do output incremental ABZ once powered on (relative to start position of course), and (b) each encoder transmits it's absolute value serially on the S phase of the encoders (RS-422) at powerup.

It sounds like if I receive the startup absolute offset from each encoder serially before starting linuxcnc, then edit the hal file for my machine and update each axis' bldc.N.encoder-offset to the (signed?) startup absolute offset from machine zero modulus the encoder positions per rev of that servo, I can then start linuxcnc and go about my merry way right? Tie bldc.N.{A,B,C}-{high,low} to some IGBT modules via Mesa PWM outputs, or bldc.N.{A,B,C}-value to H-bridges? Does that sound sane @andypugh and @dm17ry ?

Thanks everyone!
Last edit: 20 Jan 2022 22:33 by phasefreq. Reason: Grammar/clarity

Please Log in or Create an account to join the conversation.

27 Jan 2022 03:50 - 27 Jan 2022 03:54 #233252 by phasefreq
Replied by phasefreq on topic Motoman K6SB Retrofit
Having thought this through more, a simplification and a complication:

- I think, if I am remembering how this worked last time I had puma kinematics working, I can just jog each servo/joint independently until its position in steps is equal to the opposite-sign value the encoder transmitted serially at power on, then machine home/zero that joint and be done with it, right?

- Rather than cobbling together a bunch of dumb drives from half bridges, do you guys think hal latency (with Mesa realtime ethernet, say) is low enough to generate fake hall sensor or resolver signals from the encoder, and give those to a run of the mill ac servo drive?
—- Addendum to above: I have a shelf full of three phase drives that just need feedback, but I don’t appear to have any half bridges or h bridges with anywhere near high enough voltage. 
Last edit: 27 Jan 2022 03:54 by phasefreq. Reason: Clarity

Please Log in or Create an account to join the conversation.

Time to create page: 0.204 seconds
Powered by Kunena Forum