Mega V Motor Issue (X Axis)

[dreydg]

Hi all,
Just finished assembling the Mega V (with 4 axis) and I’m having problems with the x axis.
After installing UGCS and running the jogging and homing functions, the y and z work fine, but the x stays in one spot and jitters like crazy.
I have tried (to no avail):
-Taking the motor out and plugging it directly into the control box (away from other wires).
- Plugging in the 4 axis motor to see if it works (same issue)
- Trying opposite plug orientation
-Note that the motor does stiffen up and I can’t physically move it once powered on
- When jogging with large steps, the motor does turn after some jittering, but the direction it turns in is completely random.

Could this be a driver issue? Possibly something got banged up during shipping to my house?
Any suggestions are much appreciated!

[activereality]

Hmm, have you tried plugging in any of the other motors to that header on the PCB? This would isolate it being a Motor or settings issue. Also: Mega V guys speak up please (haha) Do you need to adjust the Motor Drivers?

Also, is this 'jittering' happen when the motor is physically disconnected from the machine and just electrically connected to the PCB? If it only occurs while on the machine - it is probably binding someplace along that axis - could be a number of things. 

[Bruce]

Send an email to [e-mail]
The 4th axis is totally new and may need additional configuration to switch between normal 3 axis and 4th axis mode?

[dreydg]

Mar 4, 2020 12:49:30 GMT activereality said:

Hmm, have you tried plugging in any of the other motors to that header on the PCB? This would isolate it being a Motor or settings issue. Also: Mega V guys speak up please (haha) Do you need to adjust the Motor Drivers?

Also, is this 'jittering' happen when the motor is physically disconnected from the machine and just electrically connected to the PCB? If it only occurs while on the machine - it is probably binding someplace along that axis - could be a number of things. 

Mar 4, 2020 15:48:05 GMT Bruce said:

Send an email to [e-mail]
The 4th axis is totally new and may need additional configuration to switch between normal 3 axis and 4th axis mode?

Thanks for the reply. I connected the 4 axis motor (the extra motor I have that I know works) to the header directly. The same thing happens. So I don’t think it’s a motor problem.
I also used various versions of UGCS but the same thing happens.

[Bruce]

There is a special version of Universal G-code Sender that is required to utilize the 4th axis. Look here: millrightcnc.com/resources/

[hans]

I've been using a Carve King with VCarve Desktop and UGS Platform. Works great; no issues (except for operator errors). I have a 19" x 19" Mega V (router only; no 4th axis or plasma) ready for assembly (maybe in April?) and wondered if the new UGS had any features that justified "upgrading" for my Mega V.

[dreydg]

Mar 4, 2020 17:54:51 GMT Bruce said:

There is a special version of Universal G-code Sender that is required to utilize the 4th axis. Look here: millrightcnc.com/resources/

Thanks, I downloaded that but nothing changes. To be clear, I'm only testing the X axis with different motors and seeing the same jittering/no movement problem occur.
For anyone with some technical knowledge of the control box, I've troubleshooted with a multimeter and found:

From Arduino:
-When jog left, Xdir is +4.7V, X STP goes to 2mV (this is using multimeter so PWM hard to see)

-When jog right, Xdir is 0V, X STP goes to 2mV 
-This is consistent with the Y and Z pins as well.



Using multimeter, confirmed that there is good connection between Arduino and motor controller and aviation plug header.



From motor controller to aviation header (motor disconnected): 
For X axis: When idle but power on, red and green both at -42V, black and blue at 0V. Same for Y axis. (i.e., A- and B+ are High) 
For Z and A axis, green and blue at -42, black and red at 0V. (i.e., A- and B- are HIGH)



While jogging, hard to test but all pins for X and Y showed some variation between -42 and +42 for X (except GRD of course).

Basically, X and Y controllers are acting similarly although I don't have an oscilloscope to check the pulses accurately.


BTW plugging the two motors I've used to test, into the Y output shows that they work. 

[Bruce]

So to summarize:

• When you power up the system the X motor has holding torque. But you can't get it to jog at all.
  
• Switching motors on the X axis stepper driver exhibits the same issue.
  
• Connection between Arduino and motor controller and aviation plug header is good as well as the signal looks good from Arduino breakout board to the stepper driver. (using DVM)

• All motors work if connected to the Y axis driver.

I would say there is something odd going on with the X axis driver.

Send an email to [e-mail] and reference this thread. 

[Derek the Admin]

Thanks for posting pics of it. It helps.

So, first let me say that we know it "was" working at one time because they get tested pretty thoroughly for movement and likewise for input detection. You've done some pretty good diagnostics on things. I've seen stuff show up with issues though and it usually boils down to something getting jarred on the ride to you.

The control board looks out of place as though it's bounced to the side. That would cause me to question something there, but you are getting the 5V then 0V on the direction line when you jog different directions. What happens if you take that same measurement at the stepper driver? Do you get 5V and 0V on the direction port on the driver. If you pull that do you get a good connection or not?
If you swap the green terminals between the X driver and the Y driver, do you get motion? Please try to swap the ones circled red, then the ones circled blue. Does that move the issue to the Y motor tied to that driver? If so, that tells us something has come loose at that connector (very easy fix) and not the driver itself.

With the diagnostics you've done, I assume you've also checked just to make sure its seated well.

Please let me know about the above test.

We'll get you up.
Cheers

[dreydg]

Mar 4, 2020 23:44:27 GMT Derek the Admin said:

Thanks for posting pics of it. It helps.

So, first let me say that we know it "was" working at one time because they get tested pretty thoroughly for movement and likewise for input detection. You've done some pretty good diagnostics on things. I've seen stuff show up with issues though and it usually boils down to something getting jarred on the ride to you.

The control board looks out of place as though it's bounced to the side. That would cause me to question something there, but you are getting the 5V then 0V on the direction line when you jog different directions. What happens if you take that same measurement at the stepper driver? Do you get 5V and 0V on the direction port on the driver. If you pull that do you get a good connection or not?
If you swap the green terminals between the X driver and the Y driver, do you get motion? Please try to swap the ones circled red, then the ones circled blue. Does that move the issue to the Y motor tied to that driver? If so, that tells us something has come loose at that connector (very easy fix) and not the driver itself.

With the diagnostics you've done, I assume you've also checked just to make sure its seated well.

Please let me know about the above test.

We'll get you up.
Cheers

Thanks for the advice. The control board is broken off from the supports, that's why it's off angle. Anyways before I read this, I ended up switching the A axis driver with the X axis one and that ended up working. Then, to double check, I reversed this and reconnected everything back to the way it was and it started working! 
It seems that there was a loose connection on the x driver which was hard to notice when I was forcing the multimeter probe to it. So it was a connection issue at the end.
Thanks everyone!

[Derek the Admin]

Excellent! Glad all is well. Congrats.