I'm working with twidosuite program for a few twido plc's I have in my school system. My question is how do I program the PLC to control a vfd. I can program the PLC to turn the vfd on/off but I can't figure out out to make the 0 to 10 volts for the reference signal to make the vfd ramp up and down using a set temperature. Can someone give me some pointers on how to do that. Thanks.