Overview

Every Modbus TCP explicit message performs a function. Each function is associated with a code (or number). You will need to identify the explicit messaging function by its name, decimal number, or hexadecimal number.

You can execute Modbus TCP explicit messages using either a Control Expert MBP_MSTR function block or the Control Expert Ethernet Configuration Tool’s Modbus Explicit Message Window.

NOTE: Configuration edits made to an Ethernet communication module from the Control Expert Ethernet Configuration Tool are not saved to the operating parameters stored in the CPU and, therefore, are not sent by the CPU to the module on startup.

Services

The function codes supported by Control Expert include the following standard explicit messaging functions:

Function Code

Description

Available in...

Hex

Dec

MBP_MSTR block

Control Expert GUI

1

1

Write data

X

X

2

2

Read data

X

X

3

3

Get local statistics

X

X

4

4

Clear local statistics

X

X

7

7

Get remote statistics

X

X

8

8

Clear remote statistics

X

X

A

10

Reset module

X

X

17

23

Read / write data

X

X

FFF0

65520

Enable / disable HTTP and FTP/TFTP services

X

-

"X" = the service is available.

"—" = the service is not available.