Step-Direction vs Analog Command vs CW/CCW Signals

More
07 Sep 2019 03:12 #144442 by thefabricator03
Hi Guys,

I am about start to finish the retrofit of one of my old welding robots,


The motors on the robot are Yaskawa AC servos from the early 90's. Interfacing them to Linuxcnc would be a major job because of the proprietary encoders on these drives.

Ideally I would like to replace the whole motor with ethercat AC servos but six motors and drives add up to the tune of $4000 USD.
So my next solution is to replace the encoders and use new drives to control them.

My question is about control signals, Is there any performance difference between the different control methods. The DMM drives I am using, www.dmm-tech.com/Dyn4_main.html , support many different control types, Step/Direction, Analog command and CW/CCW.

Is there a reason I should chose one method over the other?
Attachments:

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

More
07 Sep 2019 03:16 #144444 by bevins

thefabricator03 wrote: Hi Guys,

I am about start to finish the retrofit of one of my old welding robots,

The motors on the robot are Yaskawa AC servos from the early 90's. Interfacing them to Linuxcnc would be a major job because of the proprietary encoders on these drives.


Whats the drive model. Yaskawa? Usually they have the encoders going to the drive from the motor but also output quad that should work as axis encoder inputs.

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

More
07 Sep 2019 03:23 - 07 Sep 2019 03:30 #144445 by thefabricator03
This is one of two servo control boards,



As I said early 90's vintage, I dont want to be dealing with electrical gremlins from electronics that are as old as I am.

Mounting new encoders and using the existing motors is surprisingly easy, The new drives have software that I can set the parameters of the motor.

From my research the absolute encoders on these motors output a very specific pulse that only the Yaskawa drives can decode.
Attachments:
Last edit: 07 Sep 2019 03:30 by thefabricator03.

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

More
07 Sep 2019 04:49 #144449 by bevins
I have been using CACR yaskawa drives in two of my machines and they have never failed once. Just saying, they are built pretty robust. Every CACR drive I have seen has quad encoder output. doesnt hurt to try.

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

More
07 Sep 2019 04:54 #144450 by thefabricator03
I wouldn't even know where to start interfacing the old drives with linuxcnc, would you happen to have a manual for them?

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

More
07 Sep 2019 06:32 #144455 by pl7i92
the yaskawa cacb 3axis AC servo controls are standard
there are all documentation on yaskawa homepage downloadcenter

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

More
07 Sep 2019 06:44 #144457 by thefabricator03
I cannot find any manuals or anything regarding that specific drive on the yaskawa site or even google.

I think I am better off replacing the drives and encoders. At least I will have manuals for my new drives and Ill be able to tune the servos properly with the drive software.

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

More
07 Sep 2019 07:30 #144459 by thefabricator03
If I use analog commands, What Mesa card would I need for up to 8 axies?

Also with the Mesa card, will it be able to take the encoder feedback and close the loop in LinuxCNC?

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

More
07 Sep 2019 10:13 #144466 by thefabricator03
Would a 7I92H and two 7I77 analog servo card be what I would need or can I get 8 axises with other cards? The combo above would give me up to 12 axies.

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

More
11 Sep 2019 00:43 #144763 by andypugh
Are you in a hurry? If you can put this on hold for a few months there should be a new version of the STMBL drive out. That connects direct to Yaskawa servos with absolute encoders.
That should be a neat conversion with no loss of function.

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

Moderators: PCWjmelson
Time to create page: 0.187 seconds
Powered by Kunena Forum