User Documentation

User Manual Managed Switches
127
4. Using Industrial Protocols
4.1 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,
Weidmüller’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
2
Read Discrete Inputs
Internal Bits or
Physical Coils
1
Read Coils
Word access
(16-bit
access)
Physical Input
Registers
4
Read Input Registers
Supported by
Weidmüller managed
Switches
Physical Output
Registers
3
Read Holding Registers
Weidmüller switches support Function Code 4 with 16-bit (2-word) data access for read-only
information and using Unit ID 1.
Configuring MODBUS/TCP on Weidmüller Switches
Note: Modbus TCP is enabled by default. To disable Modbus TCP, uncheck Enable Modbus TCP
then click apply.
MODBUS Data Map and Information Interpretation of Weidmüller Switches