Modbus Functionality - Siemens SINAMICS S150 NEMA Operating Instructions Manual

6.12 Communication via MODBUS TCP
6.12.1 Overview
The Modbus protocol is a communication protocol based on a controller/device architecture.
Modbus offers three transmission modes:
● Modbus ASCII - via a serial interface
data in the ASCII code. The data throughput is lower compared to RTU.
● Modbus RTU - via a serial interface
data in the binary format. The data throughput is greater than in ASCII code.
● Modbus TCP - via Ethernet
data as TCP/IP packages. TCP port 502 is reserved for Modbus TCP.
With the the CU320-2 Control Unit, only transfer type "Modbus TCP" is available.

Modbus functionality

Process data and parameters are accessed via the Modbus register.
● Process data: 40100 - 40119
● Drive data: 40300 - 40522
● All parameters via DS47: 40601 - 40722
Modbus TCP always provides a basic Ethernet functionality, which corresponds to the
functionality of Ethernet interface X127:
● Commissioning access for STARTER with S7 protocol
● DCP to set the IP address etc.
● SNMP for identification
General information about communication
Communication with Modbus TCP is established via the Ethernet/PROFINET interfaces:
● X150:
For Modbus TCP with a CU320-2 PN.
● X1400:
For Modbus TCP with a CU320-2 PN or a CU320-2 DP via a CBE20.
Precisely one Modbus connection can be established. A simultaneous connection via the
interfaces X150 and X1400 is not possible and is acknowledged with alarm A08555(1).
However, you can use one interface for Modbus TCP, and the other as PROFINET interface.
Enclosed Drives
Operating Instructions, 12/2018, A5E36652151A
6.12 Communication via MODBUS TCP
Operation
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