Modbus Rtu Telegram - Siemens SINAMICS G120 Operating Instructions Manual

Parameter
p2029
p2040
7.7.3.2

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 7-18 Modbus with delay times
The data area of the telegram is structured according to the mapping tables.
Converter with the CU250S-2 Control Unit (vector)
Operating Instructions, 06/2013, FW V4.6, A5E31759476B AB
Description
Fieldbus fault statistics
Displays receive faults on the fieldbus interface
Process data monitoring time
Determines the time after which an alarm is generated if no process data is
transferred
Note: You must adapt the time depending on the number of slaves and the baud rate
is set on the bus (factory setting = 100 ms).
Configuring the fieldbus
7.7 Communication via RS485
171