MBTCP Protocol
PLX30 Series
User Manual
Ethernet and Serial Gateways
Page 94 of 200
ProSoft Technology, Inc.
September 19, 2012
6.1
MBTCP Functional Overview
The PLX30 Modbus TCP/IP (MBTCP) protocol can be used to interface many
different protocols into the Schneider Electric Quantum family of processors as
well other devices supporting the protocol. The MBTCP protocol supports both
Client and server connections.
The gateway supports a Client connection on the TCP/IP network to interface
with processors (and other server based devices) using a user constructed
command list of up to 100 entries. The gateway’s internal database is used as
the source for write commands to the remote processors. Data collected from the
processors using read commands is placed in the gateway’s database.
Data in the gateway’s internal database is accessible for read and write
operations by any node on the network supporting the MBAP (Service Port 502)
or MBTCP (Service Ports 2000/2001) TCP/IP protocols. The MBAP protocol
(Port 502) is a standard implementation defined by Schneider Electric and used
on their Quantum processor. This open protocol is a modified version of the
Modbus serial protocol. The MBTCP protocol is an embedded Modbus protocol
message in a TCP/IP packet. The gateway supports up to five active server
connections on Service Ports 502, five additional active server connections on
Service Port 2000, and one active Client connection.
6.1.1 General Specifications - Modbus TCP/IP
The Modbus TCP/IP protocol allows multiple independent, concurrent Ethernet
connections. The connections may be all Clients, all servers, or a combination of
both Client and server connections.
10/100 MB Ethernet Communication port
Supports Enron version of Modbus protocol for floating-point data
transactions
Configurable parameters for the client including a minimum response delay of
0 to 65535 ms and floating-point support
Supports five independent server connections for Service Port 502
Supports five independent server connections for Service Port 2000
All data mapping begins at Modbus register 400001, protocol base 0.
Error codes, network error counters, and port status data available in user
data memory
Modbus TCP/IP Client
Actively reads data from and writes data to Modbus TCP/IP devices using
MBAP
Up to 10 Client connections with multiple commands to talk to multiple
servers
