Cincinnati Milacron Arrow 750 Retrofit

Yes, I will be commutating based on the encoder (in absolute) and it is a brushless permanent magnet motor.

I didn't realized that "bldc" hal component can be set with offsets between encoder index and motor zero. I will look into that further.

Do I need to establish motor zero by applying +ve to servo U terminal and -ve to servo V & W or does bldc hal do it another way? (I don't get consistent motor zero when I do it this way)

Running the motor at the same speed for the same input current in both directions would hold the servo stationary at motor zero locations?

Oh, I see... Finding the correct offset is a trial and error process where you electrically spin the motor back and fourth and adjust the offset until you get the same response in both directions.

So to initially get the servo spinning using 8i20 cards, I could simply estimate the motor zero using +U, -VW and use the estimated offsets in hal "bldc" to get things started, correct?

Do you mean during initialization an accurate motor zero it isn't that critical, or after the index is read, or both?

Ok, thanks for the information!

I'm going to piece together a Hal file and try to get this servo spinning.

I managed to get the servo spinning using the 8i20 card but suddenly the servo stopped and I can't seem to get it going again. I have a red fault illuminated on the 8i20 card when the power supply is connected. I checked the fault bits in Hal Configurations and the fault.overcurrent bit is high. If I unplug the power supply and restart Linuxcnc, the fault.overcurrent bit remain low until I plug in the power supply. It then suddenly faults again. I tried unplugging the servo from the 8i20 card and the same thing happens so I don't think the servo is causing the overcurrent fault. Does anybody have any ideas or experience with this fault?