I have upgraded my system from S7 315-2 DP processor to S7 414-4H. I have a Modbus connection to DCS GE serial module IS220PSCAH1A. The data is going across to DCS, but there is an error on DCS side which says bad quality data. The module LED "ATTN" blinks red. The Modbus blocks have no errors. Block used are FB1733, 1734.