Erratic movement on steppers - need help

[maxxgraphix]

There seems to be a lot on interference between the motor drivers. I'm using a simple BOB to connect and Mach1 for software on a laptop. The powerline is filtered for the laptop and 24V power supply. When powered up all the steppers jitter. Now what's weird is that if you disconnect the Z / Y axis BOB connector the X axis works fine. By only having 1 Dir and Step connected to the BOB that one axis works fine using jog. If the BOB is not connected there are no jitters, but of course you can't run the machine.

I never got the Z axis to jog, what button do you press in Mach1. I can't find it in the help file. You can hook up the X or Y to the Z driver and it works also.

Tried TurboCNC - doesn't work at all.
Tried 3 different computers - same results
I have many other machines thar run fine in this enviroment. Wide format inkjet, vinyl cutters computers every 5 feet.

Possibilities:
1. The simple BOB doesn't work.
2. Power supply sucks
3. Stepper drivers cause a ground loop between themselves

[BigDaddyG]

Max,
As you change from computer to computer and Mach2 to TurboCNC be aware that the pin-out connections change. My guess is (and only a guess with info I have) is that your pin-outs are wrong. I would suggest:
1- Start over with the pin-outs from the computer to the BOB / BOB to the controller.
2- Check supply voltages.
3- Check 5vdc

I did the same thing, set machines up using FET-3 boards, then tried using the Gecko's on the same set up. I was convinced that I had the BOB set up correctly till I realized I had the step and direction backwards when I went from one software (TurboCNC) to the other (Mach2). Also, check that you get 4.8vdc-5vdc and .48-.5vdc as the controller switches the step and direction from the BOB. Again, if you see the voltage at 4.8 and .48 on the back side of the BOB your board is fine.

Hope this helps. I only suggest the obvious because that is what is missed sometimes.
Regards,
Glen

[maxxgraphix]

Voltage at the BOB is 4.1 and .2

So something is wrong with 5vdc at the BOB?

5 VDC is created internally by each driver, but this is just to enable / disable the drive.

Pin out - checked again for the Nth time
2 - X Dir
3 - X Step
4 - Y Dir
5 - Y Step
6 - Z Dir
7 - Z step

The motors go beserk even when the PP port cable is not connected if all are connected to the BOB.

[ger21]

Sounds like electrical noise.

I think page up and page down jog the Z in Mach2.

[coherent]

As far as jogging the Z in Mach1 or 2 try the page up/page down. That should be the default. Otherwise you can change them to whatever you want. As far a interference, it's a pain... I know because I went through it recently, but it's a matter of eliminating possible causes until you figure it out. Some other things to consider as far as noise/interference.

-Make sure it's not interference, but an overheat problem on your driver/board. If the transistors have a cycle thermal shutdown, it will cause jitters that look like interference, so check and see if the heat sinks are really hot. Does it do it when you first turn everything on when cold..if so never mind.. if it happens when things warm up get a fan or two.

- Switch motors/cables, and make sure it not mechanical in nature.

- Try it without your spindle on... many routers/spindle motors cause lots of noise. If thats the problem isolate the spindle power from the driver or computer power supply.

- Just running power lines and stepper cables close to each other can cause problems. Also just the computer itself can cause noise to nearby motor cables.

- Floresent lighting can cause noise.

- Make sure your computer isn't running other drivers at the same time, that can cause what appears to be interference. Laptops seem to be notorious for low voltage through the parallel port... try a different laptop or even better a desktop system.

- Do a bit of research on grounding and noise through ground loops. Simply isolating your driver and or breakout board(s) can eliminate problems. Ground loops can noise problems that you "think" grounding would eliminate but just the opposite is true.

best of luck!
-marc

[maxxgraphix]

I've ordered a new power supply to be sure. I thought pgup / pgdown would be it, but never worked. You can move the Z by connecting X or Y pin outs to the driver.

[maxxgraphix]

Happens cold. Nothing is getting hot.
It's not mechanical, the motors and drivers are new and work.
The spindle is not on.
Happens when I turn off all the lights.
Happens when NOT connect to a computer.

[BigDaddyG]

I am still thinking hook-up! Hate to beat a dead horse, but (If you have not done so already) check the pin-out for Mach2 because something sounds funkie about your 2 3 4 5 6 7 pins. I am at my office and have a full plate today or I could look it up, but for some reason I think there should be some breaks in the sequence, something like 2 3, 5 6, 8 9 for step and direction, with some grd (0+) thrown in there for fun. What kind of board are you using that has its own 5vdc?

[BigDaddyG]

Ok, my bad! 234567 is correct. The BOB I use connects pins as shown, but then leaving the BOB it hooks up 2 3 GRD 4 5 GRD 6 7 GRD...... Good Luck, I (most of us) know what your going thru.
Regards,
Glen

[maxxgraphix]

Mach1 sequence is 3,2 5,4 7,6 by default. Dir is still the pin 2 and Step is pin 3. So it matches my setup. The BOB does not have it's own power. Power is from the port. This thing freaks even when PP is NOT connected. So it wouldn't make any difference if I cross every single pin in Mach.

[H500]

I'm using mach and page up/dn control the z axis. I believe you need to check off the enable Z axis box somewhere in the setup.

Did you remember to make a ground connection between your laptop and the controller? I heard that many laptop parallel ports do not put out enough voltage to work with controllers. Did you try it with another computer?

Chopper drives generate a lot of electrical noise, so proper grounding is essential. Try using a star configuration for the ground. In other words, use a separate wire for each ground, all going to the power supply ground.

I made my own controller board, so I designed it with separate motor and signal grounds. It made a HUGE difference.

[maxxgraphix]

Yes, I didn't mention the GRND. Each driver has a GRND also. They connect with that cheap computer data cable. I never liked that stuff. Perhaps I'll try some shielded. I have some top notch stuff I use for DMX lighting that can carry serial data over long distances.