WEG CFW100 VFD - Control VFD using Optional Potentiometer Module - from AutomationDirect

The WEG CFW100 has an optional potentiometer module. You can use the potentiometer for whatever you want, but most of the time it is used to control the frequency of the drive or speed of the motor. And it’s super easy to set up. With power removed from the drive, remove the faceplate, and plug in the potentiometer module. Apply power to the drive. Let’s go to parameter 204 and enter a 5 to reset the drive parameters to factory default so we are all starting from the same place. Hit run – the motor starts spinning at the drive's default 3Hz which is in parameter 133. If I rotate the potentiometer, the motor speed didn’t change. If I go to parameter 20, which shows us the actual potentiometer value read by the drive, and turn the knob, we see the value change. Ok, so we know the drive sees the potentiometer value. What’s wrong? Well, we haven’t told the drive to use the potentiometer as a frequency reference yet. I’m using the drive in local mode so I go to Parameter 221 which tells the drive what to use as a frequency reference for local mode. The local mode frequency source defaults to the drive's keypad/HMI. We want the potentiometer to control the frequency, so go look in the drive's programming manual and we see that we need to enter a 3. If you have the drive in remote mode, then you would do the same thing but in parameter 222 which selects the dive frequency source for remote mode. And let’s scroll back to parameter 2 so we can see the drive's frequency. Hit run and the motor starts spinning at 3Hz again. Twist the potentiometer knob and the drive responds accordingly. Let’s crank it all the way up and the drive goes to the maximum speed in parameter 134 which defaults to 66Hz. It took a little while to get to speed which makes it feel lethargic when I turn the knob. So let’s go to parameter 100 and change the acceleration to 1 second and parameter 101 to change the deceleration to 1 second. And I’ll go back to parameter 2 so we can see the drive's frequency. Now if we turn the potentiometer the motor is much more responsive. Perfect. That’s really all you need to know for most applications. If you want to modify how the potentiometer value responds then parameter 242 modifies the gain up to 10 X, parameter 244 modifies the offset plus or minus 100%, and parameter 245 adds filtering which basically averages multiple samples over time to give you a smoother response. And while the potentiometer is normally used as a frequency reference to control the speed of the motor, you can also assign it to the built-in PLC to control whatever you program it to do there. It’s rare that you will ever need these, just know that once again, this little drive is chock-full of high-end features like this and they are available should you need them. Can you use your own external potentiometer? Sure! But, since you will be connecting it to an analog input, you will need to change parameter 221 (or 222 if you are in remote mode) to whichever analog input signal you are using, and set up that analog input channel accordingly. Of course, if you are using a CFW100 drive you will need an option module that has an analog input because the base CFW100 drive doesn’t have an analog input. This video walks you step-by-step through how to use an external potentiometer on either the CFW100 or CFW300 family of drives. Click here to see all the WEG variable frequency drive tutorials. Click here to learn about AutomationDirect’s free award-winning support options, and click here to subscribe to this YouTube channel so you will be notified when we publish new videos!