PicStep useage questions

[randyf1965]

ok, troubleshooting my 2 axis controllers that don't work

Thought I had 1 axis working but in further testing using Mach2 the stepper just vibrates back and forth never making a complete rotation.



4 wire stepper on a picstep 3.05 (3.0 - led's and resistors)

[Garfield2]

Originally Posted by randyf1965 ok, troubleshooting my 2 axis controllers that don't work Thought I had 1 axis working but in further testing using Mach2 the stepper just vibrates back and forth never making a complete rotation. 4 wire stepper on a picstep 3.05 (3.0 - led's and resistors)

Dumb question, are you sure you have your motors wired the right way? If one of the coils is back-to-front to the other the motor will not rotate but just sit there and buzz.

Alan.

[randyf1965]

The motor I am using is a Mitsumi stepper from an old dot matrix printer. wires 1&2 are 10ohms and 3& 4 are 10 ohms.

I have tried wire 1 on a2out and wire 2 on a1out and 3&4 on b2out & b1out.

I have mach2 setup so the pulse count is low, it make what appears to be 2 steps clockwise then 2 steps counter clockwise

[Garfield2]

Originally Posted by randyf1965 The motor I am using is a Mitsumi stepper from an old dot matrix printer. wires 1&2 are 10ohms and 3& 4 are 10 ohms. I have tried wire 1 on a2out and wire 2 on a1out and 3&4 on b2out & b1out. I have mach2 setup so the pulse count is low, it make what appears to be 2 steps clockwise then 2 steps counter clockwise

Yes, it sounds very much like one coil is back-to-front. You have currently

1 - a2out
2 - a1out
3 - b2out
4 - b1out

Have you tried:-

1 - a1out
2 - a2out
3 - b2out
4 - b1out

Or one of your LMD's isn't working correctly so only one coil is being energized, but the fact that it's stepping on each pulse means it's likely to be a cabling issue.

Try all this in FULL step mode (eg all mode lines shorted to ground) before venturing into the microstepping modes.

Alan.

[randyf1965]

in full step

When I jog left it buzzes slow (steps per unit 100) but when I jog right it buzzes so much faster (so fast it look stopped until I hold onto the gear then I feel it moving back and forth)



Any troubleshooting tips for a 'scope poor person?

[Garfield2]

Originally Posted by randyf1965 in full step When I jog left it buzzes slow (steps per unit 100) but when I jog right it buzzes so much faster (so fast it look stopped until I hold onto the gear then I feel it moving back and forth) Any troubleshooting tips for a 'scope poor person?

Without a scope go back to the 'old school' method and use a multimeter to buzz out all the tracks on the boards vs the schematic. Once that's done, buzz out all the tracks on the interface board. Then finally verify all the pins in the cables from the interface to the driver are correct, and also the cable from the interface to the parallel port.

Make sure there are no shorts on your boards, and also check there are no breaks in any of the traces. Failing all that and there still isn't an apparent problem, what model PIC uC's are you using (are they 16F628A's?).

Then finally, try another motor..

Alan.

[randyf1965]

Argh! I give up!!!!!

I reflowed some solder joints that didn't look good.... now it doesn't work. seeing the same resistance readings as my other 2 boards!!!

example gnd to R5 was 10k now 3 meg

I can trace the 5volt and 12 (my stepper voltage) around the board but haven't had time to sit down and theoritically figure voltage drops, etc .

Anyone have this circuit in a simulator that could be used to produce test points for a given voltage?

I have checked for shorts and traced out the board. without a known good board to get readings off I don't know how the lm18245 and the pic react to taking resistance readings

Are the LM18245's very susceptible to static damage in circuit?

Pic's are 16f628a's and I have tried 3 different motors... same buzzing

[da21]

Originally Posted by randyf1965 Argh! I give up!!!!! I reflowed some solder joints that didn't look good.... now it doesn't work. seeing the same resistance readings as my other 2 boards!!! example gnd to R5 was 10k now 3 meg I can trace the 5volt and 12 (my stepper voltage) around the board but haven't had time to sit down and theoritically figure voltage drops, etc . Anyone have this circuit in a simulator that could be used to produce test points for a given voltage? I have checked for shorts and traced out the board. without a known good board to get readings off I don't know how the lm18245 and the pic react to taking resistance readings Are the LM18245's very susceptible to static damage in circuit? Pic's are 16f628a's and I have tried 3 different motors... same buzzing

try altering the tuning of the motors in mach2 , if using the jog function in cont mode , by pressing the direction key the motor moves one step each time you press in the same direction then your motors are correct , however
stepper motors need to be tuned to get the best step rate you may be , this is just trial and error but try first of all lowering the speed right down , then if all is ok , bring the slider up bit by bit untill the motor shudders , you then have passed the optimun point , so just bring it back down untill it runs again

i would check the pcb resistance readings without the pic in place
it's much easier .

if you have MSN etc perhaps we can talk you through checking it
although i am in the UK

Dave

[randyf1965]

What is the time dif between Chicago IL USA and there 6 hours ahead?

Not bad. I will be online tonight until it works or I pass out! whichever comes first.

I think I will desolder the 2 lm18245's and ohm out everything

Is the buzz that normally happens the stepper stepping clockwise then counterclockwise? Tha tis what was happening to me it appeared to be 1 step clockwise then like 1/2 a step clockwise and 1/2 counterclockwise then 1 step counter followed by a 1/2 counter the clockwise step... repeated over and over

I adjusted the accel slider and velocity

[randyf1965]

If I press the 6 key to move to the right, I get 1 pulse in the proper direction then next press moves the opposite way.

Glad my PicStep thread got moved to the SERVO group!

[MrBean]

What do you have "Velocity" set to, in Mach2?

[randyf1965]

the back and forth motion was a problem with the pic. I have 4 pics and 2 of them cause the same back and forth issue.

Now the stepper moves smoothly 1 direction but rough and missing steps the other direction.

Any idea why that would happen?