Operating Instructions

Communication via RS485
5.4 Communication using Modbus RTU
Fieldbuses
128 Function Manual, 04/2018, FW V4.7 SP10, A5E34229197B AE
5.4.1.2
Parameters for Modbus communication settings
General settings
Fieldbus
protocol selection p2030 = 2 (Modbus RTU)
Baud rate
p2020 = 7, 19200 bit/s
Setting range: 4800 bit/s … 187500 bit/s
Parity
In the factory, the Control Unit is set for controllers with even parity You can adapt the parity
at your controller using p2031:
● p2031 = 0: No parity
● p2031 = 1: Odd parity
● p2031 = 2: Parity even
Note
Number of stop bits
For No parity, the control sends 2 stop bits, for parity odd or parity
even, only 1 stop bit
Modbus timing
p2024[0 … 2]
●
p2024[0]: Maximum slave telegram processing time:
The time after which the slave must have sent a response to the master. 0 ms …
10000 ms, factory setting = 6000 ms.
●
p2024[1]: Character delay time:
Character delay time: Maximum permissible time between the individual characters in the
Modbus frame. (Modbus standard processing time for 1.5 bytes).
●
p2024 [2]: Inter-telegram delay:
maximum permissible time between Modbus telegrams. (Modbus standard processing
time for 3.5 bytes).
Values for p2024 [1] and p2024 [2]
Table 5-10 Baud rates, transmission times, and delays (Page 131).
Fieldbus monitoring time p2040 = 1000 ms
Setting range: 0 ms … 1999999 ms
The more slaves that are connected in the network, the longer the fieldbus monitoring time
must be.
If process data is not transferred within one cycle of the fieldbus monitoring time, then the
inverter shuts down with fault F01910.
p2040 = 0 ⇒ bus monitoring deactivated.
Fieldbus error statistics r2029
Displaying receive errors at the fieldbus interface