Pmdx 126 testing

[Ed Cova]

My machine is screwed up and I don't know what the problem is.  Can I test my pmdx 126 independent of other hardware?

[Bob at PMDX]

The general answer is "yes', though the more specific answer depends on what exactly you want to test and exactly how your machine is "all screwed up".

There are LEDs on all input and output signals on the PMDX-126.  You can use those to make sure that input signals are making it through the optical isolation electronics (though this doesn't guarantee the signals make it to the parallel port pins).  The LEDs on the outputs will show you if the signal as it appears on the screw terminals is changing when you (or Mach3, etc.) command it to.

There is also a self-test mode where the push-button on the PMDX-126 board can be used to generate step signals on terminal strips J1 to J4.  See the PMDX-126 User's Manual for more information on this feature.

But before you go there, if you can give us some idea of exactly HOW your machine is not functioning, and what you've tried to do so far, we can perhaps outline some steps to try and diagnose and correct the problem.  Please include what software you are using (Mach3, etc.), how you are connecting your PC to the PMDX-126 (parallel port, Smoothstepper, PMDX SmartBOB, etc.).

Bob

[Ed Cova]

Ok I tested the motor outputs using the dip switch settings on the 126. No motors connected to the board. The direction led lights brightly the step led is dim is this normal.

[Bob at PMDX]

Ok I tested the motor outputs using the dip switch settings on the 126. No motors connected to the board. The direction led lights brightly the step led is dim is this normal.

Yes.  The step pulses are short so the LED will just glow dimly.  This shows that the step/dir signals make it from the electonics on the PMDX-126 to the screw terminals.  The next step, presuming that your problem is with the motors not moving, is to verify that the step/did signals make it from the (I presume) parallel port on the PC through the PMDX-126.  You may or may not be able to see the step pulses on the PMDX-126's LEDs, but you WILL be able to see the dir signals.  Jog an axis one direction and the "dir" LED will either turn on or turn off (depends on the configuration and which direction you jog).  Then jog that axis the other direction and the "dir" LED should change (if it was "on" it should now be "off", or vice versa).

Again, if you can give us a hint at exactly what trouble you are having then I can give you some concrete tests to run, or things to look at.  Otherwise, I'm taking pot shots in the dark.  Please also include how your PC is connected to the PMDX-126 (parallel port, SmoothStepper, PMDX SmartBOB, etc.), and which version of Mach (Mach3, Mach4 or some other software).

Bob