Help Initial Setup

[hooked]

Hi,

I'm building a new CNC router and both PMDX-416 and Mach4 are new to me.  I have built an Arduino based CNC prior to this so have some knowledge.

Getting ready to set up the control box I have plugged the PMDX-416 in and it is seen OK by MACH4.  These evening I added a M542T stepper driver and motor as per installation instructions to bench test the set up.  When I run MACH4, I get an error that the PMDX-416 cannot be found during the USB scan.  Disconnecting the M542T has MACH4 "seeing" the PMDX-416.  Have I missed a step(s)?

THANKS

Daryl

[hooked]

Further to my initial post, this is where I'm at now.

1.  The PMDX-416 intermittently looses contact with Mach4 only when connected to M542T driver and stepper motor.

2.  Jogging the motor from Mach4 just causes the stepper motor to poll.

3.  Disconnecting the stepper motor from the M542T stops the issue of disconnection of the PMDX-416.

I would love a step by step guide on how to set up Mach4/PMDX-416.......I think I'm starting to feel technically challenged!    :-)

[hooked]

Mmmm I'm not getting any responses here.

This is my wiring for testing a single stepper.  Does it look OK or am I missing something?

[hooked]

WHOOPS........apologies. I attached the wrong file......this is it.

[Steve Stallings]

The wiring in your diagram is correct.

Your disconnect problem sounds like an electrical noise issue. If
it seems to run OK without the 36 power supply turned on (but of
course the motors will not move) then it is likely noise.

Check to be sure that the power wiring to the power supply, from
the power supply to the drivers, and the wires to the motors are
not directly beside the USB cable or any of your home/limit switch
wiring.

If your computer is a desktop, try connecting an 18 AWG ground
wire from the computer chassis to the safety ground in your
controller box.

[hooked]

Thanks Steve,

I was running a test with the PMDX-416, M542T driver and PS all sitting loosely on top of the desktop computer.  I'm yet to build the control box and was just excitedly doing a quick test having received my BOB.  So, your noise diagnoses is a good call......it would I guess also explain why the stepper motor would not drive correctly.

Confirming my wiring as being correct is a relief.  I will now shelve the testing and get on with the build.

Cheers

Daryl

[Steve Stallings]

Could you describe how the stepper motor behaved again. I did not
quite understand "causes the stepper motor to poll".

[hooked]

Steve,

The stepper either ran very roughly and erratically like it was missing steps.  This would not continue for long before USB connection to Mach4 was lost.  Or, the shaft would not actually rotate but the stepper would make a noise as it was trying to drive.

Cheers

Daryl

[Steve Stallings]

Perhaps you had the Max velocity set to a value too fast for your motor?

[hooked]

Mmmm ..... not sure what's happening Steve.

I will set it up again later today paying articular attention to earthing.

Attached is the setup I'm using as supplied with my CNC plans using Mach3 and a parallel BOB. Motor setup I'm assuming should not change for Mach4.

Cheers

Daryl

[Steve Stallings]

Another possibility is an open connection to one of the windings
of the motor. With only one coil winding being powered a stepper
motor will actually try to run but will have very poor torque and
the direction that it goes is influenced by the external mechanical
circumstances rather than the CNC command.

[hooked]

Hi Steve,

I set up one motor again this afternoon starting from scratch.  I replaced the USB cable and moved everything away from the PC.  The motor ran fine.  I suspect as you have suggested one of motor coils was probably open circuit due to my wiring. 

THANKS for your guidance.  Much appreciated.

Cheers

Daryl