Author Topic: PMDX-126 Step/Dir Outputs Pinout Question  (Read 3060 times)


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PMDX-126 Step/Dir Outputs Pinout Question
« on: October 06, 2015, 03:09:43 AM »
I was wondering if it's possible to use pins 1 & 16 as step/dir pins?  I was also wondering if you can wire the e-stop to any other input other than pin 10?  The reason I'm asking is because on my smaller mill I'm testing out my Mesa 6i25 card with LinuxCNC and the firmware on the mesa card uses pin 1 as Spindle Speed and pin 16 as Spindle Dir when using Step/Dir Spindle control.  I plan on using my spare pmdx-126 board and my CNC4PC C6 spindle board.  The firmware also has the estop as pin 15. 

Thanks for all your help Bob & Steve.  I really appreciate it.  I finally have my big mill up and running and you guy's have provided excellent support to me when I needed it.  I plan on upgrading to Mach4 in a week or so I just don't know if I should buy the PMDX-410 and use it with my PMDX-126/PMDX-107 boards or buy the PMDX-422 and PMDX-407.

Steve Stallings

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Re: PMDX-126 Step/Dir Outputs Pinout Question
« Reply #1 on: October 06, 2015, 07:33:27 AM »
The PMDX-126 will allow you to use pins 1 and 16 as step and direction, so long as you do not need these pins for other functions on the board such as a PMDX-107 or the K1 relay. If you use pin 1, it is desirable to remove the jumper at JP1 so the relay does not try to follow the signal.

The E-Stop is a harder problem. The PMDX-126 will act internally to kill outputs if you remove the normally closed connection on that input. You can provide an input on pin 15 to signal E-Stop to the Mesa card. The PMDX-126 will treat it as an ordinary signal. If you have two contact sets on your E-Stop switch and use the other set to provide a "relay logic" safety circuit, then things should be OK.

You can use either a PMDX-411 or a PMDX-410 to run your PMDX-126/107 combo under Mach4. Too many choices. Sorry about that.  8-)
Steve Stallings