User`s guide

1. MODBUS/TCP MAP

Introduction

MODBUS TCP is a protocol commonly used for the integration of a SCADA system. It is also a vendor-

neutral communication protocol used to monitor and control industrial automation equipment such as PLCs,

sensors, and meters. In order to be fully integrated into industrial systems, Moxa’s switches support

Modbus TCP/IP protocol for real-time monitoring in a SCADA system.

Data Format and Function Code

MODBUS TCP supports different types of data format for reading. The primary four types of them are:

Data Access Type

Function

Code

Function Name

Note

Bit access

Physical Discrete Inputs

Read Discrete Inputs

Internal Bits or Physical

Coils

Read Coils

Word access

(16-bit access)

Physical Input Registers

Read Input Registers

Moxa Support

Physical Output

Registers

Read Holding Registers

Moxa switches support Function Code 4 with 16-bit (2-word) data access for read-only information.

Configuring MODBUS/TCP on Moxa Switches

Type 1

Select the checkbox and click Activate to enable the Modbus TCP.