Malcolm,

I believe you have just highlighted my error!!

On the 568 I have disabled all sources except D1 and A1, labelling them Dig and Anlg (I assumed the 562V handled the sources and directed them to the appropriate output)

It looks like the correct way forward is for the sources to match on both the 568 and 562, except on the 568 point them at the appropriate D1 or A1 input on the 568

I will test this evening.

Thanks for the assistance, greatly appreciated.

S