I checked run08 pp 283 runs data to get the pedestal values for each strip. The run list is here. I selected several strips to check the pedestal value variations with the time. The following plots are pedestal values VS the run index where the run index is dependent on time.

   Fig1, U pannel sector 2 strip 1.

       Fig2, U pannel sector 2 strip 11.

       Fig3, U pannel sector 2 strip 21.

       Fig4, U pannel sector 2 strip 31.

     It's obivious that the pedestal changed with time but not so frequently. There several runs for these 4 strips that the pedestal is around 100. This need to be make sure whether this means these runs are not good for data analysis.