Modbus Rtu Telegram; Baud Rates And Mapping Tables - Siemens Sinamics G120P Operating Instructions Manual

6.8.3.2

Modbus RTU telegram

Description
For Modbus, there is precisely one master and up to 247 slaves. The master always starts
the communication. The slaves can only transfer data at the request of the master. Slave-to-
slave communication is not possible. The Control Unit always operates as slave.
The following figure shows the structure of a Modbus RTU telegram.
Figure 6-21 Modbus with delay times
The data area of the telegram is structured according to the mapping tables.
6.8.3.3

Baud rates and mapping tables

Permissible baud rates and telegram delay
The Modbus RTU telegram requires pauses for the following cases:
● Start detection
● Between the individual frames
● End detection
Minimum duration: Processing time for 3.5 bytes (can be set via p2024[2]).
Inverter cabinet units
Operating Instructions, 12/2014, A5E32923362A
Operation
6.8 Communication via RS485
233