I'm at the point where I need to fire up the computer so I can configure and test the electronics. Before I do that I'd like some feedback on my wiring and initial configurations. Don't want any smoke to get out! Some notes first. I left in place the VFD wiring for my On/Off switch, Fwd/Rev switch, and potentiometer. For those VFD terminals shared between manual control and Mach3 control I spliced the wires together. I'm still reading through the PMDX and ESS manuals and searching the net. Still have some configuration to do such as spindle pin assignment, ESS configuration, and more. Here are my wiring and initial settings: Drivers to PMDX-126 (J1, J2 and J3) Step signal to Pin 8, 6 and 4 on J1, J2 and J3 Dir signal to Pin 9, 7 and 5 on J1, J2 and J3 Enable signal not connected 115VAC to PMDX-126 (switch set to "115") Probe wire to J12 Pin 15 (ground is through spindle) Limit switches to J12 Pin 11 (wired in series) Limit switch ground to adjacent GND terminal E-stop wire to J13 "E-stop" Pin E-stop ground to adjacent GND terminal JP1 set to Pin 1 JP2 set to Pin 14 JP3 set to OFF JP4 no jumper provided JP5 set to OFF JP6 set to NORMAL PMDX-126 SW1 Config 1 - Open (Off) Config 2 - Closed (On) Config 3 - Closed Config 4 - Closed Config 5 - Closed Config 6 - Closed Config 7 - Open Config 8 - Open PMDX-107 to VFD (Hitachi WJ200) SW1 - all off Rev/Dir to VFD terminal 2 (logic input) Fwd/Run to VFD terminal 1 (logic input) Com to VFD terminal P24 (+24V for logic inputs) Aref to VFD terminal H (+10V analog reference) Aout to VFD terminal O (analog voltage input) Agnd to VFD terminal L (GRND for logic inputs) Mach3 Spindle Setup Disable Relay Control - Checked Use Spindle Motor Output - Checked PWM Control - Checked (I'm thinking this should be Step/Dir Motor based on my PMDX-107 wiring) PWM Base Frequency - 25 Minimum PWM - 5% Spindle Motor Tuning Steps per - 1000 Velocity - 60 Acceleration - 5000 Pulley Selection Pulley 1, Min Speed = 0, Max Speed = 8625, Ratio = 2.5 Pulley 2, Min Speed = 0, Max Speed = 1380, Ratio = .4 Thanks, Tom S.