Command transmission
Commands can be sent from the central station in control direction (to the substation).
A single command with type ID 45 (C_SC_NA_1) is used for controlling an application object that is transferred in monitoring direction as a single-point information (M_SP_NA_1, M_SP_TA_1 or M_SP_TB_1). A dual command (C_DC_NA_1) is used for controlling an application object that is transferred in monitoring direction as a double-point information (M_DP_NA1, M_DP_TA_1 or M_DP_TB_1), etc.
Configuration of the system parameters:
No special system parameters need to be set;
Configuration of the application objects:
The application objects must be configured as commands (data types in the control direction);
The addresses of the information objects (IOAs) must correspond to the addresses in the control station;
Examples:
Single command with the IOA 10. The value received is copied into the flag range buffer, byte offset = 100, bit offset = 0.
F_iecInitAOEntry( C_SC_NA_1, 10, 0, 0, MAP_AREA_MEMORY, 100, 0, AODB[24] );
Double command with the IOA 20. The value received is copied into the flag range buffer, byte offset = 200, bit offset = 0 to 1.
F_iecInitAOEntry( C_DC_NA_1, 20, 0, 0, MAP_AREA_MEMORY, 200, 0, AODB[27] );
Set point, scaled value with the IOA 60. The value received is copied into the flag range buffer, byte offset = 600 to 601, bit offset = 0.
F_iecInitAOEntry( C_SE_NB_1, 60, 0, 0, MAP_AREA_MEMORY, 600, 0, AODB[39] )
The associated PLC example tutorial can be downloaded here.