🎛️ Adjusting PWM Input Settings on the Delixi EM61 VFD for Accurate Spindle RPM Control

If your spindle RPM isn’t matching the values output by your controller (Longboard, GRBL, Duet, etc.), it’s likely due to PWM-to-analog signal scaling mismatch between the controller and the VFD. This guide shows you how to adjust the minimum and maximum voltage settings inside the Delixi EM61 VFD to better align your spindle RPM feedback with your controller’s commands.

📦 Why This Matters

When your CNC controller sends a PWM signal to control spindle speed, it typically does so by converting that signal to a 0–10V or 0–5V analog signal using a converter (often built into the controller).

But your VFD must be told what voltage range to expect. If your VFD assumes 0–10V and your controller only outputs 0–5V, your spindle will never reach full RPM — even if your G-code says S24000.

⚙️ Typical Analog Input Ranges

We preprogram your vfd if you told us ahead of time what controller you're using with your system. 

If you did not, you’ll want to match the VFD’s input range to your controller’s actual analog output range.

🧰 Adjusting the Analog Input Range in the VFD

Here’s how to change the VFD parameters to properly scale analog input:

Minimum Input Voltage (set to 0.10V)

This ensures the spindle doesn’t spin when your controller outputs its idle/minimum signal.

• Parameter: P2.0.13

• Set to: 0.10

This tells the VFD to treat anything equal to or less than 0.10V as "0 RPM" or spindle off. Anything below 0.10V will be ignored.

Maximum Input Voltage

Choose 5.00V or 10.00V depending on your controller’s full-scale output.

• Parameter: P2.0.15

• Set to: 5.00 or 10.00 depending on your controller

This tells the VFD, “When the analog input reaches this voltage, treat it as 100% speed.”

🎯 What This Fixes

• Spindle running slower than expected at max RPM

• RPM not scaling linearly with software output

• Inconsistent cutting performance due to low spindle torque

• Confusion between expected and actual speed readings

📺 Video Walkthrough

We've made a short, focused video that walks you through these exact settings inside the Delixi EM61 VFD menu:

🧠 Pro Tip

After adjusting the voltage range:

• Run a few test M3/M5 commands from your controller

• Check spindle RPM at S6000, S12000, and S24000

• Verify the RPM on the VFD display matches what you expect (±5%)

You can use a laser tachometer if you want to double-check accuracy.

🛠️ Related Articles

• Can I Run a 2.2kW Spindle on 110V? →

• How to Break In Your Spindle Motor →

💬 Need Help?

If your RPMs still feel off or your spindle isn't reaching expected speeds, contact support and let us know your controller, analog output range, and spindle type — we’ll help you get dialed in.