Jazcnc thanks very much for the very informative post I've learnt a lot

Next daft question does anyone know what the actual difference is between the leadshine em806 drives and it's predecessor the am882 and also the dm870?

The first two appear to be the same (hence is there a diff paying extra for the new one when the old one is still being sold new) and the dm870 appears to not offer sensorless stall detection although that is only above 300 rpm which for a direct drive application is a bit fast in my plasma application. Is it worth it is there anything else different?

Thanks again for your time and hope you have a happy christmas

Jonathan is current not consistent. Input must equal total output? But measuring the input would be smoother than measuring just one of the channels