Accessing COE data with DPV1 services

DPV1 MSAC-C1-READ and DPV1 MSAC-C1-WRITE can be used for read and write access to all COE data. The COE data must allow READ and WRITE access.

The access is always via two DPV1 telegrams. The first is always a DPV1 WRITE telegram. The second is a DPV1 READ telegram. The DPV1 WRITE telegram determines which COE data are read or written.

Behavior when the Bus Coupler is restarted Please note that the COE data, which are changed by your controller, have to be re-sent to the terminal when the EK3100 Bus Coupler is restarted.

• Reading data: During reading a DPV1 WRITE telegram is send to the Bus Coupler. It notifies the Bus Coupler which data are to be read. The second DPV1 READ telegram is then used to fetch the data.
• Writing data: During writing, the data are transferred with the CoE parameters, and the acknowledgement of the COE write access is transferred with the DPV1 READ telegram. This consists of 4 bytes. If these are zero, the data were written without error. If they are not zero, an error has occurred.
  
  The error corresponds to an ADS error code. The meaning of the ADS error codes can be found in the TwinCAT documentation (see: ADS error codes).