I built up a DP-Profibus master system with S7315-2DP with several ACS800 drives. Everything seems OK, there is no bus fault, but there is a constant "COMM MODULE FAULT" on every drive. I can read the information from PZD1 and PZD2 with PLC but when I try to enter a value for PZD3 in drive it turns back to zero after refreshing the data. Is there anybody who has an idea of what I did wrong? I use PPO type 4 and DP mode is 1. The version of GSD file is 10812. Will appreciate any kind of help.