AKD F702 fault and Workbench Fieldbus cycle time unable to adjust

Hello,

-At our plant we have a product line that have 8 AKD servo drivers connected via PROFINET to PLC's (all are s7-300) and other equipments like RFID reader, camera etc. So they all are on same network. So, F702 fault frequently occurs. Their "IO Cycle -> Update Time" setting is 16000ms. (that can be seen at "akd_hwConfig" picture attached). 

-My other problem is; when we connect to one of drivers with Kollmorgen Workbench and try to change Fieldbus cycle time parameter, it just doesn't allow us. Parameter set itself to 0 and when we try to change it, it keeps show the error "The value is out of range". And writing valid number doesn't work.(You can see the error at "akd_bug") We don't know if it's a bug or need to do something before change it. We are sure that plc doesn't write the parameter, we disconnected the driver and tried again, no chance.

Thank you for your help.