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PMDX-422 help please
« on: June 17, 2020, 08:21:51 PM »
Hi All,

I purchased a basket case router that has a PMDX-422 Rev A1 and 3 4A drives for the steppers.

Nothing was connected to the machine so I decided to test the PMDX and drives before I started the rebuild.

I have a updated the PMDX and installed Mach4 Hobby demo version and the PMDX seems to be working.

I have a 24V psu connected to one drive and the moter connected to the drive.  The PMDX is USB powered.

My question is how do I connect the 4 inputs on the drive to 3 outputs on the PMDX and what should the 3 way jumper be set to +5V or GND and do I need to common the whole lot together somehow.

Thanks for your help, I am not daft just confused by new terminology.
YP

Offline MN300

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Re: PMDX-422 help please
« Reply #1 on: June 18, 2020, 08:41:04 AM »
Here is a connection diagram for positive logic. ( not inverted )

Jumper set to GND.
Software set for STEP on even pins.
If you can assign an output for ENABLE the stepper motor current will be off when the drive is not enabled. Otherwise connect it to 5V.

If you are running the wiring a long distance the pair of wires from each drive input should be in shielded cable.
Re: PMDX-422 help please
« Reply #2 on: June 18, 2020, 11:55:37 AM »
Thank you for the help.

I have the drive wired as shown and I now have a new question.

If I enter G01 G91 X1. F10. and cycle start the drive steps round and the white line on the knob stops at the point it started,  if I change the F10. to F20. the same but quicker.  If I change it to F30. the shaft is jumping back and forth and stops in random places.  Change it to F40, 50, 100, 200 even 300 and its spot on again.

Setting are steps/per 200
Velocity 2000
Accelaration 100
Driver set to 1:1 stepping

My question :- do steppers have a no go speed?

Also is it possible to attach video to the forum?

Thanks
YP

Offline MN300

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Re: PMDX-422 help please
« Reply #3 on: June 18, 2020, 12:12:26 PM »
You may be seeing stepper resonance - look it up online.
If you are testing with just a knob on the motor shaft be aware things will be much different when you connect it to the proper load.
You can attach a link to a video you place on YouTube or a similar site.

Offline Bill_O

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Re: PMDX-422 help please
« Reply #4 on: June 18, 2020, 12:14:20 PM »
We also need to know how sw1 to sw6 are set.
Re: PMDX-422 help please
« Reply #5 on: June 18, 2020, 02:10:24 PM »
Thanks again,

now I am happy the supplied kit works I can install it in the machine and then fine tune it.

Here are the pictures of the switches.
 

Offline Bill_O

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Re: PMDX-422 help please
« Reply #6 on: June 18, 2020, 02:30:55 PM »
Hard for me to see but it looks like you have it set to 200 steps per rev so your 200 steps per unit should have done one revolution.
2000 rpm is fast for a stepper motor.
Slow your velocity down to 500 and acceleration to 50 and try again on the moves.
Having said that the velocity should not come into play unless you are doing a G0 move.
The acceleration will probably need to be 50 or lower though.
For one of our machines I have some very strong steppers being fed high voltage.
I max them at about 900 rpm and an acceleration of 50.
Re: PMDX-422 help please
« Reply #7 on: July 04, 2020, 12:44:30 PM »
Are those those cheap TB6600 drivers like mine, can't tell.  My Vec is set at 200, Acc 28 and its micro stepping x8, my steps per unit of Measure or 1 inch is 5110.   That is for a direct drive screw for a router, yes it works fine and I set it up with a dial indicator for steps calibration per inch.

« Last Edit: July 04, 2020, 12:50:12 PM by wmgeorge »
Retired Master Electrician, Commercial HVAC/R Service and lots of Hobbys.