Reason for not using diode protection on COUT's?

Kevin 7 years ago in Master modules updated by Gustav Widén (System support) 7 years ago 1

What is the reason for not being able to use diode protection on COUT's? The manual for the MC3 for example states 'Do not install diodes across the coils', just wondering why this is noted, is there a specific reason?

Also there are a selection of other methods of suppression, resistors etc. Can resistors be used? In terms of diode suppression, is the TVS diode not to be installed in the same way as say a standard diode is not to be used?

All the IQAN COUT:s are designed with built in diodes between the CRET pins and the COUT high-sides.

If you add an external diode this will interfere with the current measurement. The absolute accuracy on the COUT will not be nearly as good. I am guessing that and external diode could also lead to problems with the COUT diagnostic functions, but I have never tried this myself.