I thought that this would be a common problem, but it turns out that few folks have posted a solution that works, at least for this popular VFD.
I have run this using a MEGA, controlling a Teco 510 VFD. I needed to control a sizable motor using an Ardunio. Simple functions, STOP, FORWARD, REVERSE, and of course, Frequency.
Hope it works for you as well as it has for me. Of course, use at your own risk, and your mileage may vary, etc.
TecoVFDControlFunctionsPub.ino (8.49 KB)