GS4 Variable Frequency Drive Control from the Built-in PLC - Live Demo Part 1 at AutomationDirect

Let’s walk through this example in the examples folder which set’s the drive’s frequency, acceleration and deceleration times, Enables the drive, issues the run/stop, and forward and reverse commands. It also does a drive fault reset. I moved my menu buttons to make more room on the screen so don’t be surprised if my screen looks different than yours. If you don’t see the comments, then make sure the show comments button is on. Rung 0 says when we set the internal general purpose M1 bit, set the frequency and ramp times. I can never remember which register is which, so let’s right click and edit the register comments. D50 is the frequency with two implied decimal places. D52 is the acceleration with two decimal places and D53 is the Deceleration also with two implied decimal places. Ahh, that’s much better. Of course, these D registers will need to be pre-loaded with these values before running this command. In this example, we’ll do that with the register monitor when we go on line with the drive. That rung used 8 of our 10,000 steps, so the next rung starts at step 8 where we use input X0 to enable the drive. That’s not the RUN STOP Command – it just enables the drive’s outputs. The comment says “power On” – think of that as applying power to the output stage of the drive. The row comment reminds us that X0 is what the drive refers to as the Forward input and use that input as the drive enable by enabling this special function register output coil. The next row uses the drives Reverse input as the RUN/STOP control by enabling this special function register. The next rung uses this input X2 to control forward and reverse via this special function register and this rung uses X3 to reset a fault. Lets select the com port that our USB to RS485 adapter is plugged into … these are the correct comm parameters and we do want RTU. Perfect. Let’s write this program to the drive, go online, and open the monitor window. Let’s add the M1 Control Register and the Frequency, Acceleration and deceleration registers. Let’s set the drive’s frequency at 60 hertz – remember the two implied decimal places – and the ramp times to be 5 hz. Again, with two implied decimal places. Let’s toggle M1 to set the frequency and ramp times. I have some switches connected to the drives inputs, so I’ll enable X0 to power up the drives output, Set the forward switch and set the run switch. And sure enough, the drive ramps up to speed over 5 seconds. Perfect. Well ... That’s really all there is to it … BUT … there are a number of things you need to know to get the most out of your GS4 drive when controlling it from the built in PLC. We’ll cover all of that in Part 2. Click here to learn more about the GS4 drives. Click here to learn about AutomationDirect’s free support options. And click here to subscribe to AutomationDirect’s YouTube channel so you will be notified when we publish new videos.