eight_bools
Lifetime Supporting Member
Hey Guys,
I have a pair of machines that we are converting from potentiometer speed control to PLC control with an analog output card. PLC is a SLC 5/05 and and VFD is a PowerFlex 525.
I took some reference speeds to get the VFD frequency and parts per minute to come up with a formula. Its working okay but depending on the desired run speed in parts per minute the operator enters I am a little bit off. Not a huge deal but it would be nice if it was more accurate.
I am using the compute instruction and the formula below. Just wondering if there is a better way of doing this. I also attached a printout of the logic we used, its pretty basic. I tried searching for some sample logic online but didn't have much luck.
Max Analog Value/Max Frequency=Analog/Hz
32768/90 = 364.089
Average Parts/Hz = 0.119
(Parts/Min x 0.119) x 364.089
I have a pair of machines that we are converting from potentiometer speed control to PLC control with an analog output card. PLC is a SLC 5/05 and and VFD is a PowerFlex 525.
I took some reference speeds to get the VFD frequency and parts per minute to come up with a formula. Its working okay but depending on the desired run speed in parts per minute the operator enters I am a little bit off. Not a huge deal but it would be nice if it was more accurate.
I am using the compute instruction and the formula below. Just wondering if there is a better way of doing this. I also attached a printout of the logic we used, its pretty basic. I tried searching for some sample logic online but didn't have much luck.
Max Analog Value/Max Frequency=Analog/Hz
32768/90 = 364.089
Average Parts/Hz = 0.119
(Parts/Min x 0.119) x 364.089