⚠️ Troubleshooting: Masso Not Controlling Spindle RPM Automatically

If your spindle runs manually but fails to respond to automatic RPM commands from your Masso controller, follow these steps to diagnose and resolve the issue.

✅ This guide assumes manual spindle control works as expected.

🔌 Step 1: Confirm Control Cable Connections

• Make sure the control cable is securely connected at both ends:

  • Masso (Elite model): Use the correct port on the bottom of the controller or refer to this diagram:
    Control Cable Inlet Diagram →

  • VFD: Connect as shown in your system’s wiring diagram.

🔁 Step 2: Set Manual/Auto Switch to “Auto”

Check that the Manual Override Switch on the VFD is set to automatic control mode. If it’s in manual mode, Masso will not be able to adjust RPMs.

⚙️ Step 3: Verify VFD Parameters

Ensure the following VFD parameters are correctly set:

P0.0.03 = 1  
P0.0.04 = 3  
P0.1.00 = 8  
P0.1.01 = 2  
P2.0.00 = 1  
P2.0.01 = 2  
P2.0.02 = 21  
P2.0.03 = 18  
P2.0.29 = 01

🔍 Step 4: Test PWM Output from Masso

To confirm Masso is sending the correct PWM signal:

1. Disconnect the control cable from the VFD side.

2. Use a multimeter to test the PWM signal at the cable:

   • Red lead: PWM pin

   • Black lead: Ground pin

   • Reference orientation: With the notch at the top, top-right is Ground, the pin to the right of it is PWM (clockwise).

3. In Masso software, command a spindle RPM (e.g., 12,000 or 24,000):

   • At 12,000 RPM, you should read around 5V.

   • At 24,000 RPM, you should read around 10V.

If readings are correct here, Masso is successfully outputting the signal.

🧪 Step 5: Trace the Signal (if no voltage is found)

• If you don’t see the expected voltage, test closer to the Masso unit:

  • Start at the inlet connector on the machine.

  • If voltage is present at the Masso-side inlet but absent at the VFD end, the cable is likely faulty and should be replaced.

🔄 Step 6: Check CCW (Counterclockwise) Operation

Sometimes only clockwise (CW) is wired. Here's how to test CCW:

1. Connect the CCW control wire:

   • If using PwnCNC's wiring harness: Green wire = CCW

   • Inside Masso: White wire = CCW (floating inside the case)

   • For Onefinity Elite: Blue wire = CW, White wire = CCW

   • See our Masso – Onefinity Wiring Notice for proper configuration.

2. In Masso, command a CCW RPM using:

   M4 S6000   ; Start spindle counterclockwise at 6000 RPM  
   M5         ; Stop spindle

    

🧪 Optional Test: Manually Trigger the VFD

To confirm the VFD reacts to control inputs:

1. With no RPM commanded:

   • Disconnect the PWM wire (Pin 1).

   • Disconnect Pin 5, then touch it to the screw terminal of Pin 4.

   • You should see the VFD display show a solid "0" or similar, indicating it’s receiving a valid signal.

This also applies for checking Pin 7, depending on your control setup.

📌 Summary

• ✅ Confirm connections are correct

• ✅ Verify VFD parameters

• ✅ Test PWM signal from Masso

• ✅ Check cable integrity

• ✅ Ensure CCW signal is properly wired

• ✅ Use manual tests as a last step to isolate VFD behavior

Still stuck? Reach out to us at [email protected]—we’re happy to help walk you through it.