We’re trying to control a Variable Frequency Drive (Mitsubishi d720s) with Arduino.
The VFD as a 24V control signal circuit, where activating pins triggers functions on the VFD. We’re attempting to use a MOSFET based circuit, such that we can map the 5V digital-write pins on the Arduino to the various input signals (STF, STR, RH, RM, RL) on the VFD.
Our circuit work with a separate 24V circuit (activating a lamp f.ex.), but when connect to the VFD it seems to be unable to fully activate the MOSFETs.
Also, we can’t really make out what should be the common ground for the Arduino and the MOSFETS, we tried placing it in the SD sink of the VFD, but with out success.
20170506_ludo, circuit.pdf (477 KB)
irf3708pbf_eng_tds.pdf (278 KB)