Hello everyone. I have a inverter configuration problem I thought someone here might be able to help with. I'm not looking for a specific solution for my inverter in question, but rather if anyone has encountered this problem and has generic parameter advice to give.
I'm using a Mitsubishi FR-D720S-070SC-EC inverter to control a small 1.5 kW blower. Blower moves air through a filter and Mitsu is using PI-controller to increase flow as filter gets dirtier.
I have my PI-controller setpoint on a 0-10V potentiometer and 4...20 mA process value coming from a differential pressure transmitter. Now, the whole setup works fine... unless the pot is at its minimum setpoint value at 0 V. If the potentiometer is at minimum value, simply nothing happens if I block the filter. The controller is alive and conscious as I can view the controller error value on the Mitsu screen, however error refuses to rise above its rest value which would start to increase the flow. If I increase the setpoint any non-zero value, no matter how minimal, then the controller starts working properly.
I've been banging my head on this but I'm pretty much out of parameter changes to try. I've replaced the inverter but that was not the problem. Most annoying part is that according to my notes I used this exact setup in 2017 and back then there were no problems...
I'm using a Mitsubishi FR-D720S-070SC-EC inverter to control a small 1.5 kW blower. Blower moves air through a filter and Mitsu is using PI-controller to increase flow as filter gets dirtier.
I have my PI-controller setpoint on a 0-10V potentiometer and 4...20 mA process value coming from a differential pressure transmitter. Now, the whole setup works fine... unless the pot is at its minimum setpoint value at 0 V. If the potentiometer is at minimum value, simply nothing happens if I block the filter. The controller is alive and conscious as I can view the controller error value on the Mitsu screen, however error refuses to rise above its rest value which would start to increase the flow. If I increase the setpoint any non-zero value, no matter how minimal, then the controller starts working properly.
I've been banging my head on this but I'm pretty much out of parameter changes to try. I've replaced the inverter but that was not the problem. Most annoying part is that according to my notes I used this exact setup in 2017 and back then there were no problems...
