AD620 - pot assembly alternative - filter
The pot assembly shown in your diagram will slightly imbalance the strain gauge bridge and produce errors that may be too high. The conventional way to "manage" offsets is to adjust the ref pin input with a pot - this has no detrimental effect on imbalancing the bridge as it only affects the output stage of the AD620.


  QUESTION :Can i replace the pot assembly with anything else ?is there
  an Alternative ?


Many, many times I have used the output of a DAC for driving the ref pin and it always works for me. I guess a digipot would also work but both these suggestions require the use of a microcontroller (MCU) to perform an auto zero i.e. press a button and the MCU adjusts the output by measuring it until it is 0V as set by the DAC.

Another way, if you don't mind the continuous removal of the DC content of the signal is to use an integrator loop from output to ref pin: -