I'd like to add an input to MACH3 that does exactly what a limit switch input does. I want it to switch off the ENABLE (DB25-1) but leave the charge pump running (the check box is on in the config menu).?? So not quite the same as the ONLINE button.

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I want to logically OR the servo motor fault outputs so all motion stops but power is not switched off. ?

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To do this I have to remove the FAULT input to the PMDX-126 which creates an ESTOP event and shuts off servo motor power.

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A limit switch type event is more appropriate for my system.? I could logically combine say the Z upper limit with the fault and just settle for the incorrect error message but I'd rather have the input generate a message that says "Fault Input Active".

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Is there a way to do this with MACH3??

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Thanks

John

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"ELS! Nothing else works as well for your Lathe"

Automation Artisans Inc.

www dot autoartisans dot com

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Hi Chuck,

Thanks for the reply.? I do have an A axis (Harmonic motor run with STMBL AC Servo drive) and although I may well add a home position switch to it I hadn't thought about using one of the other unused limit switches.?

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I currently use a small PIC12F609 micro-controller to monitor the DC Servo power, ENABLE from the system and the FAULT outputs from the servo.? With only 6 pins I'm limited in what I can do but changing the /FAULT output to the inverse FAULT active high is really easy.

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For that matter I can just declare the limit switch input as active high rather than active low since a broken wire to a switch isn't an issue with this.? Don't even have to change the firmware then.

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The reason for the PIC controller was that I have a soft start on the DC servo power supply so it takes a second or so for it to come on after the master power is applied.? Problem is that the Charge Pump and ENABLE output show up before the power supply is up to voltage.? It's not a problem for the HP_UHU DC Servo motor driver but is for the STMBL AC Servo drive which uses the same 105VDC power.?? It faults out when it gets the EABLE because the power supply voltage is still too low.?

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So I get this cycle of PMDX-126 gets ENABLE and switches on K2 relay which supplies relay control to the AC/DC power circuits and MACH outputs the ENABLE signal on DB25-1 out to the drives.?

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The STMBL AC Servo Drive sees low DC voltage and asserts /FAULT into the PMDX-126 Fault input.? The PMDX-126 /FAULT forces an ESTOP from that input and that shuts off the control relay for the AC/DC power circuits.? AC/DC goes bye-bye.? MACH is in RESET and then undoing that starts the whole cycle over again. ?

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By adding a delay on the FAULTs based on the DC voltage I get around the STMBL issue.? There were a few other problems but that was the biggest.

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