Thanks, didn't think of that.
The voltages were 10-40mV. Ah, I was thinking millivolts, but I think mA is micro volts.
That threw me I think.
I'll check for noise
@ JohnRob
As far as grounds, it's the same if I connect them all or not. I read that they share gound in the scope, at least with generator.
Hmm, but that don't make sense. You could have different circuits. ???
I've checked both ways here on this one.
Thanks for replies.