I am finishing up the transition from Mach3 to Mach4 with a PMDX and ESS upgrade. The last step before I can button things up is the Spindle PWM. With a potentiometer hooked up to the VFD 10v+, ACM and AVI, I can control the spindle speed. My original setup only had two wires going to the VFD (AVI and ACM). I connected the PMDX like the previous card to AVI and ACM with a 5v max.

Should I be able to run the CFD with just two signals?

No matter what I do, I don't think the power is getting ti the VFD because the two cards don't share the right ground. A voltmeter shows power at the terminals, so maybe. The VFD and PMDX are both grounded to the machine. The control signals are coming from the PMDX on a terminal block that has pc GND which is different from the shared ground mentioned previously.

Does the PMDX need to share a pc gnd with the VFD?

If you have this setup or could shed some light it would be much appreciated!

I made a little progress since the previous post. When using the 'motor on' mapping in the ESS and again in Mach4. I can turn the spindle on and off. Where I am now having an issue with PWM. In the ESS config I map a pin to 'motor pwm' and in mach there is no corresponding mapping so I am left to hope the stars align. My PWM pin always shows 0v so I feel I am missing something.

If you are running an ESS with PWM to a VFD I would love to know a little more about your ESS setup and MACH4 config.

The relay outputs and analog control voltage from the PMDX-107 are isolated from the PCgnd and no connection to PCgnd is needed. The ACM signal on the VFD is the ground reference for the analog control signal.

The PMDX-107 has an on-board power inverter and can operate in two wire mode without the VFD 10v+ signal from the VFD. There is a DIP switch setting to control to select 5 volt or 10 volt mode when operating as a two wire interface. If the 10v+ signal is connected, then it will override the switch setting and 10 volt analog signal will be generated.

In all cases, we recommend that you use the Test button on the PMDX-107 to diagnose wiring and VFD configuration because the Test modes are internal to the PMDX-107 and are not affected by the Mach and SmoothStepper software configuration.

The SmoothStepper PWM management in Mach3 was a little unusual in that it REQUIRES a setting for acceleration of the spindle. If it is left at zero, then the spindle will not spin up. I am not sure if this is true of the Mach4 SmoothStepper plugin.

Documentation about the Mach3 / SmoothStepper / PMDX-107 setup can be found in this application note:

http://www.pmdx.com/Doc/AN002_PWMSpindleSmoothStepper_02.pdf

@Steve, Thank you for your response. I don't think I mentioned that I am using a PMDX-126. The relays are being used to change the spindle direction. I am open to picking up a 107, but I wanted to see if I could run my spindle from the ESS and 126. If I can get a variable voltage signal (via pwm or otherwise) from the 126 to my VFD I will be good to go. Maybe I am getting mixed up in the motor type selection and pin mapping.

It never occurred to me that you did not have a PMDX-107. You can use the relays to control On/Off and Direction, but the PMDX-126 will not produce an analog voltage signal by itself. You may be able to get your VFD to work by using external components to filter a PWM signal to become an approximation of a 5 volt analog speed control signal. This would require a connection from PCgnd on the PMDX-126 to the ACM of your VFD. Depending on your VFD, this may cause isolation and noise issues.

@Steve,
Thanks for the information. I moved the ACM from 5v+ to the PCgnd. Still no movement. I have things set up (to the best of my knowledge) so that the ESS is producing a PWM signal to Port1 Pin16 on the PMDX-126. When I turn on the Would that produce an analog signal from the PMDX or is it not designed to be used that way? Do you know the proper ESS and corresponding Mach4 settings for a PWM spindle?

Everything is working! There was an issue in my Mach / ESS config but I got it sorted (set the motor pwm and hope it maps). The ESS outputs 5v max but the VFD expects 10v. In the VFD I set the max voltage to 5v and now my spindle is working! My controller card conversion is complete! Now it is time to calibrate the machine...