Author Topic: Dmm Dyn4 pmdx-126 connections  (Read 4807 times)

Ltdan

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Dmm Dyn4 pmdx-126 connections
« on: October 26, 2016, 08:18:03 AM »
Hi all
I'm new here
Do I use pc ground on jp1-4 for my shield wires from my drive?
Also my drives have 4 wire for pulse dir two for + two for neg. Do I tie the 2 + connections together for +5volt then pulse- direction- to there individual inputs?
Thanks
Dan

Ltdan

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Re: Dmm Dyn4 pmdx-126 connections
« Reply #1 on: October 26, 2016, 08:38:34 AM »
Here is a pic of dyn4 i/o
It says to shield to jp4 shell which is the body of db25 cable which is what I want. Pmdx126 connection pcground or ?
Thanks  sorry to double post thought this would help clear up my question.
« Last Edit: October 26, 2016, 08:43:26 AM by Ltdan »

Bob at PMDX

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Re: Dmm Dyn4 pmdx-126 connections
« Reply #2 on: October 26, 2016, 09:03:55 AM »
You should connect the shield to GND on one end of the cable only!  Otherwise you can get ground loop current flowing through the shield which makes it a source of interference instead of a shield.  The sample connections on page 16 of the manual say to ground the shield on the receiver side, which is the DYN4.  So I would say do not connect the shield to the PMDX-126.

Unless you can prove that the shield is NOT connected to the DB25 shell on the end that plugs in to the DYN4.  Use an ohm meter to measure resistance from the shield to the metal DB25 shell, close to zero ohms means it is connected.  Infinite or very large readings means no connection.  In that case, there will be no shield connection to the DYN4 and you can connect the shield to the "PCgnd" terminal on the PMDX-126.

Regarding the PUL+/- and DIR+/- wiring, you have 2 options:
[edit 28 Oct 2016 - see also our FAQ on this:
http://faq.pmdx.com/content/3/11/en/how-should-i-connect-pul-pul_-dir-and-dir_-on-my-motor-drivers.html?highlight=pul]

(1) Tie the PUL+ and DIR+ together and connect to the "PC+5" terminal on the PMDX-126.  Then connect the PUL- and DIR- to the step/dir pins on the PMDX-126.  This corresponds to the "Open Collector (external power supply)" example in the DYN4 manual.  If you do this you must configure Mach to have the step pulses "active low".  The direction polarity will depend on how you have your motors wired.  Pick a polarity and see if the motor moves the direction you expect.  If not, change the DIR polarity.

(2) Tie the PUL- and DIR- together and connect to the "PCGnd" terminal on the PMDX-126.  Then connect the PUL+ and DIR+ terminals to the step/dir terminals on the PMDX-126.  This scheme is not shown in the DYN4 manual but should work.  Configure Mach to have the step polarity "active high" (or "not active low").  The direction polarity is the same as the previous case - i.e. you just have to test it and see which setting is correct.

Bob
« Last Edit: October 28, 2016, 12:41:54 AM by Bob at PMDX »
Engineering Hell: Everything's right and nothing works.
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Ltdan

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Re: Dmm Dyn4 pmdx-126 connections
« Reply #3 on: October 26, 2016, 10:14:10 AM »
Thank you Bob!