Prosoft card communicating with 2 seconds delay in L63 processor

I have a Rockwell L63 processor setup. For encoder communication I have started migrating from SST module to Prosoft MVI56- PDPMV1 module. I am able to communicate well but receiving data from prosoft card with a little delay of 2 seconds. How to reduce the delay ?
Note: I tried varying rpi for prosoft module varied from 5 to 750ms but of vain.
Installed profibus cable length: <200m
 
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