I have 3 AC grounded signals (60Hz 0-5V) in differential configuration in Chanels AI0-AI8, AI2-AI10, AI4-AI12 with ground to AISENSE and to COM as recommended in user manual for 9205. These 3 signals share the same ground reference.
and 3 AC floating signals (60Hz 0-5V) in differential configuration in Chanels AI1-AI9, AI3-AI11, AI5-AI13, with 22k bias resistors for every line to COM.
All readings for the floating signals get saturated.
But If I change the connection order as follows I get apparently good readings:
the 3 floating signals in Chanels AI0-AI8, AI2-AI10, AI4-AI12
and the 3 grounded signals in Chanels AI1-AI9, AI3-AI11, AI5-AI13
It seems that Channels AI0-AI8 should always have a floating signal connected. Why?
How does the modul 9205 manage these connections and ground references? Or what I am doing wrong.