Generic Modbus Controllers

Starting in version 1.1 of the MBTCP OI Server, additional Modbus devices that are not listed in the supported hardware will be supported. These Modbus devices, referred to as Generic Modbus devices/controllers in this document and in the implementation of the OI Server, must be capable of supporting the Modbus Controller Function Codes, Modbus Exception Codes, and Data Types.

Compared to the Schneider PLCs listed in Supported MBTCP OI Server Hardware and Firmware, the Generic Modbus devices/controllers offer the following additional capabilities:

• Configurable TCP Port Number.

• Support of Modbus devices that cannot handle multiple-coil write in one message.

• Support of Modbus devices that cannot handle multiple-holding-register write in one message.

• Configurable 4-digit, 5-digit, or 6-digit addressing.

• The maximum addressable register range will be verified by the Modbus devices and does not need to be configured into the OI Server.

• Access to data in Modbus PLCs that support 64-bit data types such as integer and floating point value data types. In support of accessing 64-bit data types, the order of the PLC memory registers written to and read from are configurable.

• Configurable Zero Based Addressing to enable addressing both in Modbus PLCs that are zero-based, such as the TSX Premium, and in Modbus PLCs that are one-based. Zero-based addressing means that the first address bit (character) begins at 0 rather than at 1.