Denford Triac VMC with ATC Conversion / Fix

[Chaz]

I was going to say I never had any major E-Stop issues with my Denford Cyclone lathe (from what I've seen, Denford used a pretty standard E-stop setup across most of their machines), but then the KFlop allowed me a lot more flexibility in handling E-stops, and I added extra relays so the servo fault outputs triggered an E-stop. However to achieve clearing a drive fault situation, I had to use a custom program in the KFlop that clears the E-stop signal, then waits for all the drives to exit fault status before resuming normal business.
I used Kinco servos from Zapp, which allowed me to configure inputs/outputs how I wanted them to work, but I'm not sure what drives you're using, or what timing sequence they need.
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I'm guessing your problem is the Drive Enable/Drive Fault timing once you're into an e-stop?
Your DER should be connected to a Drive Enable output from Mach3, so unless Mach is active, nothing should move. Simplest option may be to add an override push button to disconnect the drive fault input and/or trigger the drive reset so you can fool Mach into exiting an e-stop, and get the drives back online/out of fault.

Yep, spot on. Mine is about DER timing I feel. As the Denford uses inverse logic, its been a bit more painful as the CS Labs unit cannot provide 'switch on this 0V option' from what I can see. I also dont understand why, when Mach3 goes into 'reset mode' that the machine moves itself in X and Y positive direction. I think disabling the drives will help here, currently the DER relay is kept powered (well, zeroed, 24V is permanent) via hardwiring. Ill swap the logic and then use one of the enable outputs, like what I am doing with the new Kinco drive that replaced a damaged IRT drive.

[m_c]

Yep, spot on. Mine is about DER timing I feel. As the Denford uses inverse logic, its been a bit more painful as the CS Labs unit cannot provide 'switch on this 0V option' from what I can see.

Just swap the relay wiring. Instead of having the relay having a permanent 24V with switched 0V, swap it so it's got a permanent 0V with the 24V coming via the CS.

also dont understand why, when Mach3 goes into 'reset mode' that the machine moves itself in X and Y positive direction. I think disabling the drives will help here, currently the DER relay is kept powered (well, zeroed, 24V is permanent) via hardwiring.

That's the way analogue drives work. When the controller is active and running closed loop, it's continually adjusting the supplied voltage to hold the servo stationary, remove the closed loop or disconnect the control wire, and most servos will move, due to the internal circuit design and/or even interference/noise generate in the wiring. That's why the drive should be disabled when the controller isn't active. Most modern servo drives do let you program in a 'deadband' zone, which allows you to create a voltage range where the drive will not move, but it's not something that's needed when a CNC controller is involved. It's a feature more aimed at where servos are being manually controlled via something like a speed pot, where you need a stationery position from a basic voltage control.

Ill swap the logic and then use one of the enable outputs, like what I am doing with the new Kinco drive that replaced a damaged IRT drive.

One thing to note with the Kinco drives (certainly the CD4x2 ones I used), is you can invert the input/output logic via the software. IIRC by default, things like fault outputs are only activated on a fault (bad choice from a failsafe point of view, as it means any fault in the fault circuit could cause the fault signal to go unnoticed), but can be swapped by clicking the suitable button on the input/output config screen (that's not the correct name, but I've not got the software installed to check just now!)

[Chaz]

Just swap the relay wiring. Instead of having the relay having a permanent 24V with switched 0V, swap it so it's got a permanent 0V with the 24V coming via the CS.

That's the way analogue drives work. When the controller is active and running closed loop, it's continually adjusting the supplied voltage to hold the servo stationary, remove the closed loop or disconnect the control wire, and most servos will move, due to the internal circuit design and/or even interference/noise generate in the wiring. That's why the drive should be disabled when the controller isn't active. Most modern servo drives do let you program in a 'deadband' zone, which allows you to create a voltage range where the drive will not move, but it's not something that's needed when a CNC controller is involved. It's a feature more aimed at where servos are being manually controlled via something like a speed pot, where you need a stationery position from a basic voltage control.


One thing to note with the Kinco drives (certainly the CD4x2 ones I used), is you can invert the input/output logic via the software. IIRC by default, things like fault outputs are only activated on a fault (bad choice from a failsafe point of view, as it means any fault in the fault circuit could cause the fault signal to go unnoticed), but can be swapped by clicking the suitable button on the input/output config screen (that's not the correct name, but I've not got the software installed to check just now!)

Thanks, agreed on swapping polarity, done that with the Spindle Relay already.

On the Kinco, I cant get my Serial / USB cable to work, so its all been done by hand. Sometimes the drive doesnt like being reset and I need to fiddle a few times.