Analog Inputs Part 3: Helpful Hints for the GS4 Variable Frequency Drive (VFD)

Appendix C of the user manual has tables that list every parameter for each I/O in one simple concise location. These are great to use as check lists to make sure you don’t forget anything when you are setting parameters. While we did all of the analog input videos using keypad entry, remember that all of this could be done using the free GSoft2 Software that you can download from AutomationDirect.com. There is a whole separate video that shows you step by step exactly how to use that GSoft2 application to configure and operate the drive. Because Analog Input 3 can handle plus and minus 10 volts, it does gain differently than analog inputs 1 and 2. Gain and offset for inputs 1 and 2 are just the equation for a line. The gain is the slope and the offset is the y intercept. The difference is analog input 3 has a gain parameter for the positive side and another parameter for the negative side. That’s handy for when you have a process that normally runs in one direction, but you want to limit the max possible speed in the other direction using a negative voltage as an input. A good example of this is a reverse jog where you use the negative voltage for the reverse direction. Analog inputs can be easily affected b noise. Best practices are: Use Shielded wire Connect the shield to ACM terminal – especially if noise is from an inductive source Grounding the shield at the drive end is all you need. Don’t ground the other end of the shield because you can create a current loop that will just create more noise. Keep wire away from long parallel runs with power lines or other noise inducing wires. If noise is coming from the AC motor drive, consider adding a capacitor and a ferrite core like this. Make sure the wire is wound around the core at least three times. More if possible. Check this out: Do a search at AutomationDirect.com for EMI/RFI Techniques. It’s a white paper that discusses: The different types of EMI, Sources of EMI, What types of devices suffer from EMI, How to measure EMI, and excellent check list of all the things you can do to help mitigate EMI and RFI issues. The terminal board switches that switch analog inputs 1 and 2 between current and voltage are backwards from each other. Analog input 1 has voltage in the up position, analog input 2 has it in the down position. So don’t assume they work in the same direction. Analog inputs can be used for PID Set Point, feedback, or offset. That’s a big topic by itself so it is covered in a separate video. This is a cool feature. If you remove these two screws, the terminal board can be pulled out to make wiring easier. When done, just push it back in until the connector mates and re-insert the two screws. That should to be enough to get you going. Click here to learn more about the GS4 Drive. Click here to learn more about AutomationDirect’s free support options. And click here to subscribe so you will be notified when we publish new videos!