Author Topic: Y-Axis (Motors 3A & #B) Not Turning  (Read 3285 times)

bwolfe

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Y-Axis (Motors 3A & #B) Not Turning
« on: August 10, 2018, 04:48:25 PM »
I can't get my Y-Axis motors to turn, which I have mapped to Motors 3A & 3B.  I am trying to use the PMDX-424's hardware cloning facility. 

I have:  PMDX-424, two (2) PMDX-133's, PMDX-407 (which is currently not mounted and is disabled in Mach4 until I've tested everything else).  I have Mach4, the PMDX-Smart BOB-USB Plug-in, Gecko g203V drivers & NEMA 34 motors.  I have installed the latest versions available and the latest firmware.

I wired the PMDX-133 #1 board to the PMDX-424 with the ribbon cable to J6.  PMDX-133 #1 is daisy chained to PMDX-133 #2.  The drivers are connected as follows using Steve Stallings instructions in another post, with one exception, noted below.

PMDX-424 Motor     PMDX-133
Motor0                    PMDX-133 #1, Axis #1-  NOTE: I AM NOT USING THIS AXIS, NO GECKO, NO MOTOR AND I DIDN'Y MAP IT IN MACH4
Motor1                    PMDX-133 #1, Axis #2
Motor2                    PMDX-133 #1, Axis #3
- - - - -                     PMDX-133 #2, Axis #1 - NOTHING CONNECTED HERE
Motor3a                  PMDX-133 #2, Axis #2
Motor3b                  PMDX-133 #3, Axis #3

Mach4 Screen configurations- PMDX-Smart-BOB-USB Plug-in Configuration-
Motor Configuration/ Step/Dir Pin-out:  I checked "Swapped (normally for PMDX-133 or PMDX-134 on J6)"
Feature Configuration, PMDX-424 hardware Motor Cloning:  I checked "Enable (Motor 3A & 3B steps enabled)."

Mach4 Control Configuration-  Axis Mapping
X(0) Enabled-  Motor 1
Y(1) Enabled- Motor 3
Z(2) Enabled-  Motor 2
A(3)  Not enabled

I used MDI and gave each motor a G-code command to move 1 inch, each separately (G0 X1.0, then stopped and ran G0 Z1.0, then stopped and I ran G0 Y1.0) .  The X-Axis motor and Z-axis motors turned, but the Y-axis motors do not.

On the Mach4 screen, it showed that the Y-axis motors were turning, but physically they weren't.

Since I have both PMDX-133 set up with Geckos in connector positions 2 and 3, I tried directly connecting the ribbon cable from PMDX-424 J6 to the input connector on PMDX-133 #2.  Then I used the G-code commands to move the X and Z axis motors, but physically, those Geckos were still wired to the Y-axis motors.

Those motors turned ok when used as X & Z, but not as Y-axis.

I also tried swapping the ribbon cables.

Again since both PMDX-133's have their respective Geckos in the same positions, I tried daisy chaining PMDX-133 #2 output to PMDX-133 #1 input.  I commanded the X & Z axis motors to move, but again had them actually wired to the two Y-axis motors.  They turned.  But when I commanded the Y-axis to move, nothing moved.

On the Mach4 screen, it showed that the Y-axis motors were turning, but physically they weren't.

What am I doing wrong?

bwolfe

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Re: Y-Axis (Motors 3A & #B) Not Turning
« Reply #1 on: August 11, 2018, 02:54:47 PM »
My brother checked the step & direction signals coming out of the PMDX-424 J6 Ribbon cable header with an oscilloscope while I gave each axis a G-code command to move in the MDI screen.

Regarding the designations "Axis #5" and "Axis #6" in the PMDX-133 manual, the outputs for step and direction coming out of PMDX-424 J6 are swapped with each other compared to what is documented for the corresponding input pins on the PMDX-133's J10 connectors.  In other words, the Direction pins have pulses, and the Step pins are either "low" or "high".

I'm putting the results into an Excel file to send to Steve.

And by the way, the hardware configuration- the placement of my Geckos- was actually in a forum post by Bob, not Steve.  Sorry for my misstatement.