TOS-KURIM CNC Upgrade

[m_c]

Sounds more like some kind of hardware issue.

I'd try swapping motors, then drives, to see if the problem moves or stays.

[Muzzer]

Yes, I'd start swapping over the motor / encoder etc. Sounds like a buggered component or a wiring fault, crossed over wiring etc. Time to go for a process of elimination etc.

IIRC, you fitted your own encoders. Getting those wired up correctly would be helpful. That must be a fairly likely candidate.

[JimJam]

I've attached a photo of the encoder just so you can verify it's even suitable for this application..

So the encoder wiring is labelled up as:

Brown: 5 - 24VDC
Blue: 0V Common
Shield: GND
Black: OUT A
White: OUT B
Orange: OUT Z

This is wired to the line driver module to convert to differential signals. I have attached a photo of the wiring info for this, but all it is is ground, A, 5 Volts, and B. so I have this wired up as:

Ground: Blue: 0V Common
A: Black: OUT A
5 Volt: Brown: 5 - 24VDC
B: White: OUT B

From there it is just a standard RJ45 cable that plugs into the drive unit. I have also tested the cables I'm using with the proper tool to verify the wiring is correct.

I have also attached the pin outs for the RJ45 side of the line driver and the servo drive encoder input.

[JimJam]

Just noticed after I posted that, looks like I may have the + and - the wrong way around on the A and B inputs from the line driver to the servo drive!

EDIT: Would this actually cause any issues though? or just result in opposite rotation?

[m_c]

Just noticed after I posted that, looks like I may have the + and - the wrong way around on the A and B inputs from the line driver to the servo drive!

EDIT: Would this actually cause any issues though? or just result in opposite rotation?

As long as you've still got the A/B paired correctly, direction is the only thing that could be affected.

[Muzzer]

And as noted before, you need to be sure the cables don't cross over any of the conductors.

[JimJam]

Progress! You may remember a while ago I tried extending the encoder cables with some CAT5 cable I bought which turned out to be the cause of an earlier issue. I used the same cable to make up the RJ45 cables that link the encoders to the drives.

I have no idea why I didn't replace these earlier when I had the other issue, but swapping them out for some bought patch cables has stopped the motor juddering..

I stripped back the outer insulation of a piece of the cable from the reel and every now and then there is a break in the conductor but the insulation remains in tact! which I can only assume was enough to make a contact when I tested the cables but mounting it on the machine must have given it an intermittent connection.

Now back to the tuning!

[Muzzer]

Well I suppose a smart arse would point out that network cables aren't exactly industrial grade flexible cables, being single core etc. In my own defence, I only used it in my own system within the cabinet for the short distance between the line driver and the DG4S drive.

Good you found the issue in the end. It could have been even more intermittent which would have been even more frustrating. With intermittent faults you can never be 100% certain you've found and fixed the issue.

That cable sounds surprisingly crap if it has multiple breaks straight off the reel. You need to get the whole thing out of the building and into a skip where it belongs before you use any more of it now or in the future.

That video of swarf can only be hours away now - looking forward to seeing it in action!

[JimJam]

Yeah, I’ve learnt my lesson there! Out of interest what would have been the best cable choice for this application?

Is there flexible cable available that would work with the RJ45 plugs?

[m_c]

Igus supply pretty much any kind of flexible cable you can think off, however you may want to be sat down when looking at some of the prices.