I have designed a circuit using AD620 putting in unity gain and giving i/p as 0V - 10V with supply +15V and -15V and ref = 0V (GND).
In fig2 m dividing 400V to 10V and feeding it to AD620.
When I test these channels separately the o/p is OK.
But when I simultaniously swiched ON both inputs The AD620 in fig 1 shows 1.2V increament in its o/p irrespective of the i/p.
When I swiched of the 400V i/p the o/p of the AD620 in fig 1(upper one) came back to original.
As I understood from the datasheet is the ref pin can be given to GND and did the same in both the cases.
There are 4 channels of each of these ckts on my board and I have given same GND to all ref pins of AD620.
Please suggest me the changes I need to do so that the variations on one channel should not affect the other channel.
Thanks and Regards,