Data and register types

When a client sends a read/write request to the MBTCP Communication Driver, the Communication Driver needs to know its data type and size. In order to determine this information, the MBTCP Communication Driver parses the item name to get the register number, data type, and size. The Communication Driver builds messages with items sorted by PLC, register type, register number, and topic name, allowing the Communication Driver to optimize the number of registers that can be read in one scan command.

The following table contains the types of data for the Modicon controllers, TSX Quantum, TSX Momentum, TSX Premium, Generic Modbus (4-Digit, 5-Digit, and 6-Digit), Compact 984, and Modicon Micro, supported by the MBTCP Communication Driver.

Note: The unsigned integer data type "U" has a valid range of 0 (zero) to 2147483647 when accessed through DDE/SL client; for OPC clients the valid range is from 0 to 4294967295. System-defined types are not supported as block reads. A read on any of these data types returns only the first element.

The following table lists the PLC register types, the data types contained in the registers, and what each is processed as.