When using SCADAPack x70 devices, it may be desirable to pack 16 bits into a Modbus holding register. This is typically wanted when the SCADAPack is acting as a Modbus Server. When using RemoteConnect, all protocol facing values need to be in “objects” in the SCADAPack database.

Logic:
If you need to pack 16 bits into a Modbus holding register, a user will create an object associated with a Modbus address. The Logic Variable Type will be “T_SPx70_UINT”.
In the logic editor, the user will use a combination of “BIT_TO_WORD” and “WORD_TO_UINT” function blocks. The inputs to the “BIT_TO_WORD” block can be a combination of Elementary variables and Derived variables that are part of the x70 object database.

Below are visual examples of the objects and logic needed to bit-pack an object with up to 16 bits. The 16 bits will be available in Modbus register 40001 (object ModbusBitPack). Any SCADA/RTU/PLC client can poll for Modbus register 40001 and get the bit-packed value.

Udgivet til: Schneider Electric Danmark