# Setting the C4 Value
## Why set the C4?
Every Stagehand motion controller sends an analog speed signal to the VFD telling it how fast to go. Depending on the Stagehand type, this same signal also describes the direction the motor should spin. These speed signals are called Unipolar (speed only) and Bipolar (speed and direction).
* The Stagehand Pro 3 &4 and Stagehand Apprentice utilize a 0-5vdc speed signal with seperate direction switches.
* The Stagehand Classic and Stagehand Pro 2 utilize a +/-10vdc speed and direction signal.
In either case, the Mitsubishi VFD needs to be calibrated to the analog speed signal coming in so that 100% speed signal results in 60hz output to the motor. Some models have been calibrated at CCI HQ and have a label on the back or on the VFD Keypad showing the value that should be entered in Parameter C4.
## Set C4 from A Known Value
{% hint style="success" %}
CCI puts a small "**C4: XX.X"** sticker in the top, left corner of the rear of the Stagehand enclosure **OR** along the top or side of the VFD Keypad
{% endhint %}
[How to Use the VFD Keypad](https://docs.creativeconners.com/docs/stagehand/stagehand-parameters/how-to-use-the-mitsubishi-vfd-keypad)
1. Press 
until the display reads **P.0**
2. Rotate 
**CCW** until you get to **C….** Press 
3. Rotate **CW** until you get to **C4.** Press
* The screen will display a value of X.X (close to 0.0)
4. Rotate **CW ONE CLICK** to view the current C4 value (Default is 100)
5. Rotate **CW** to your known C4 value. Press to confirm value
6. Cycle power to the VFD
## Set New C4 Value
[How to Use the VFD Keypad](https://docs.creativeconners.com/docs/stagehand/stagehand-parameters/how-to-use-the-mitsubishi-vfd-keypad)
{% hint style="success" %}
The Stagehand does not need to be connected to a motor to run the calibration sequence.
For any Stagehand Pro controller:
1. Set **Pr. 800 (control method) to 20**
2. Unplug your motor cable
3. Set your **C4 Value (below instructions)**
4. Set **Pr. 800 to 0**
{% endhint %}
5. Press until the display reads **P.0**
6. Rotate the **CCW** until you get to **C….** Press
7. Rotate the **CW** until you get to **C4.** Press
* The screen will display a value of X.X (close to 0.0)
8. Jog the Stagehand forward to 100%
9. Continuing to hold the FWD Jog at 100% and **press the** **key on the VFD keypad**
* Wait a moment for the VFD to beep and flash between your new value and **P C4**
10. Release the FWD Jog button
11. Cycle power on the VFD
{% hint style="success" %}
Make a label with this number and place it on the back of the cabinet. This number is unique to this drive and gets reentered in C4 if the drive ever gets reset.
{% endhint %}
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