System parameters

The common ASDU address and the user functions of the central station are configured via the system parameters.

In our introduction we configure the following system parameters:

• The common ASDU address is set to 7. (asduAddr);
• The octet length of the cause of transfer is set to 2 (1 octet for COT + 1 octet for source address) (eCOTSize);
• The octet length of the common ASDU address is set to 2 (eAsduAddrSize);
• The octet length of the information object address is set to 3 (eObjAddrSize);
• Logging of debugging messages in the application log is activated (dbgMode). Changes in the device status and error messages of the link layer are logged;

Add the following PLC code to your PLC project:

IF init THEN
    init := FALSE;
...

     client.sysPara.asduAddr := 7;
    client.sysPara.asduFmt.eCOTSize := eIEC870_COT_TwoOctets;(* cause of transfer octet size *)
 client.sysPara.asduFmt.eAsduAddrSize := eIEC870_AsduAddr_TwoOctets;(* common ASDU address octet size *)
 client.sysPara.asduFmt.eObjAddrSize := eIEC870_ObjAddr_ThreeOctets;(* information object address octet size *)
 client.sysPara.dbgMode := IEC870_DEBUGMODE_DEVSTATE OR IEC870_DEBUGMODE_LINKERROR; (* IEC870_DEBUGMODE_ASDU OR IEC870_DEBUGMODE_LINKLAYER *)

...
ELSE
    client( pInputs := ADR( inputs ),
        cbInputs := SIZEOF( inputs ),
        pOutputs := ADR( outputs ),
...

END_IF

The documentation for all system parameters can be found here: ST_IEC870_5_101SystemParams.