Sevenfins Posted February 1, 2018 Report Share Posted February 1, 2018 So, I'm new to Unitronics and pretty much PLC in general, and I am doing a project for school. I have everything else complete in it (To the best of my current knowledge) with the exception of: The program calls for a fan to ramp up to whatever speed when the heat in the furnace reaches a certain degree, and the fan is supposed to run in forward and reverse during the duration of the wash cycle. I have looked for help and have yet to find any on my end, thus why I turn to the internet. Any explaination would be great. Quote Link to comment Share on other sites More sharing options...
MVP 2023 Joe Tauser Posted February 1, 2018 MVP 2023 Report Share Posted February 1, 2018 I'm assuming the fan is on a VFD. The fan ramp can be done with a linear block driven by an MI counting time. What is the ramp rate? After the fan reaches speed, use two timers alternating each other to trigger the reverse input on the drive. I'm also assuming you've programmed accel and decel times in your drive to handle reversing the fan. If you're not too shy to post your code it would be very helpful. Joe T. Quote Link to comment Share on other sites More sharing options...
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