Siemens SIMATIC S7 CP340 - MODBUS RTU Protocol Communication; MODBUS Slave Protocol Communication of CP341; Before and after Inserting Dongle

5 MODBUS RTU Protocol communication
CP340/CP341/CP440/CP441 Communication and Programming
Entry-ID: 88867653, V1.0, 02/2014
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 Siemens AG 2014 All rights reserved
5 MODBUS RTU Protocol communication
MODBUS RTU communication protocol is in master-slave mode. In the
transmission process, the master sends a request telegram actively to the slave,
and the slave returns an answer telegram. For details of MODBUS RTU protocol,
please refer to related MODBUS RTU files or manuals.
5.1 MODBUS Slave protocol communication of CP341
5.1.1 Hardware catalog
PS 307
6ES7 307-1EA00-0AA0
CPU 315-2DP
6ES7 315-2AG10-0AB0
MMC
6ES7 953-8LG11-0AA0
CP341
6ES7 341-1AH01-0AE0
Dongle
6ES7 870-1AB01-0YA0
Dongle's support is necessary when using CP341 for MODBUS Protocol
communication. Before it is used, install Dongle in the Dongle slot at the back of
the CP341 module. Dongle and CP341 before and after inserting Dongle are
shown as in the Fig. below:
Fig. 57: Before and after inserting Dongle