Schneider Electric TSXCUSBMBP Modbus Plus Communication for Applications, Introduction, Port VSP

Overview

Modbus Plus Communication for Applications

Introduction	Most Win32 applications that support serial Modbus communications can
	communicate on a Modbus Plus network with the TSXCUSBMBP.
Virtual Serial
	A Virtual Serial Port (VSP) is used as the mechanism for redirecting communications
Port (VSP)	from programs such as Concept, Unity, and ProWorx32 to the TSXCUSBMBP
	adapter. The VSP presents the same interface as a standard serial port to the
	software. As such it is indistinguishable from a physical serial port.

Modbus Plus

Communication-

Process

The Modbus Plus Communication process is described in the following table:

Stage Description

1After the VSP is installed, it will create one serial port with the port reference (COM1- COM12) defined in the TSXCUSBMBP Driver software.

2When configuring the Modbus application software, this port reference for the VSP is selected as the serial port for the application to use.

3The TSXCUSBMBP Driver will then work like a Bridge Multiplexer to redirect serial Modbus Plus messages onto a Modbus Plus network, but at a much faster rate since no serial communications are actually taking place.

Illustration:
Windows XP
Operating System
Application	Virtual	TSX C	USB-MBP	USB
	Serial Port	USB MBP
Software			Driver	Controller	USB
	Driver	Driver
					Cable

USB-MBP

Modbus Plus Network

Routing Table A routing table similar to that used by Modicon's BM85 Bridge Multiplexer is used to associate Modbus Slave IDs with 5-byte Modbus Plus routing paths. This allows the application software to communicate with any Modbus Plus device within range on a Modbus Plus network.

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