CI522 MODULE COMMUNICATION IS NOT STABLE WITH PM573 ETH PLC

We are using CI522 module for remote I/O communication with PLC CPU PM573 ETH.we are facing the communication instability between CI522 module with PLC CPU PM573. The data is updated from CI522 to CPU PLC for few minutes. then it holds the same value in PLC CPU as CI522 is not updated to PLC CPU. When we restart the PLC CPU then CI522 is being updated actual values to CPU for next one hour. please support me to solve this issue.