Machine moves by itself

More
17 Aug 2022 16:12 #249956 by Ingo
Replied by Ingo on topic Machine moves by itself
Sorry, I don't know if I understood your question correctly, but I'm using a generic parport board, the drives and servos are Chinese with a reasonable quality, Action brand but it is imported and nationalized with this name….

I don't know if it's a coincidence or not, but I have the impression that it got worse when I put a USB extension (it's 5 meters, it's shielded), because I need a point on the front of the panel.

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

More
17 Aug 2022 16:47 #249958 by Todd Zuercher
So your drives and motors are step/dir controlled via the parallel port?

And I'm assuming there is no position feedback into Linuxcnc?

Are you using any breakout board between the parallel port and the drives? If so which one?

The problem is most likely electrical interference causing the drives to pick up noise as false step and or direction signals.

Are the drive's step/dir inputs supposed to be differential signals? Is it optional to configure them as either single ended TTL or differential?

You may need to reexamine your entire wiring and grounding scheme. Including hi-voltage and pc wiring.

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

More
17 Aug 2022 17:29 #249961 by Ingo
Replied by Ingo on topic Machine moves by itself
Yes the drives are controlled through parallel port with step/dir.

Yes LinuxCNC does not have position feedback.

I'm not using any breakout board (is it necessary to use it? if so which one would be more suitable?).

The step/direction signal cable is shielded, it goes from the parallel port is TTL to the drive is SCSI.

I will check every part of the panel related to power and control….

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

More
17 Aug 2022 17:40 #249962 by Ingo
Replied by Ingo on topic Machine moves by itself
Hello,

I don't use the 7i77 but a generic parallel port, how would the drive enable routed please?

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

More
17 Aug 2022 18:11 #249963 by Todd Zuercher
It is quite probable that your drives are set up to see a 5v signal, and your parallel port may only be suppling a 3v signal. (and a weak pull up to that 3v at that). Resulting in a border line signal that is very susceptible to noise. Using a parallel port beakout board that offers true 5v buffering of the output signals may go a long way towards improving your results.

They don't have to be expensive. A pretty good one is a C10 bob made by CNC4PC. But even an inexpensive generic Chinese Mach3 5-axis bob will often be an improvement over nothing.

Another option might be to simply add 5v pull ups to the parallel port outputs (parallel ports are usually better at sinking than sourcing current.)

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

More
17 Aug 2022 18:40 #249965 by tommylight
Replied by tommylight on topic Machine moves by itself
Does the DRO in LinuxCNC change position/numbers when that happens?
If not, it is not a LinuxCNC issue, it is a drive issue.

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

More
17 Aug 2022 19:52 - 17 Aug 2022 19:54 #249971 by smc.collins
Replied by smc.collins on topic Machine moves by itself
what part numbers for drives? how are they configured ?? 

you should probably consider some kind of encoder feedback 
Last edit: 17 Aug 2022 19:54 by smc.collins.

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

More
19 Aug 2022 03:11 #250049 by Ingo
Replied by Ingo on topic Machine moves by itself
Exactly that Todd my card is configured with 5v and my computer is already sending 3v and the card doesn't have a signal filter that goes straight to the drive…. Sorry I didn't understand two things what would be a beakout board and another would be pull ups?

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

More
19 Aug 2022 03:36 #250050 by Ingo
Replied by Ingo on topic Machine moves by itself
That Tommy the DRO remains stationary on LinuxCNC. As I don't have feedback control, I left volatile_home in true, I use it for all axes but especially for the Z axis (vertical), if you press the emergency this is useful, but in the case it moves alone it makes no difference.

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

More
19 Aug 2022 03:44 #250051 by Ingo
Replied by Ingo on topic Machine moves by itself
Sorry Collins I didn't understand your question, did you ask the model, serial number of the drives? Worse than I have no feedback signal control…. this control only with another encoder or digital scale?

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

Time to create page: 0.252 seconds
Powered by Kunena Forum