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Configuring the fieldbus
6.2 Communication via RS485
Frequency inverters with Control Units CU230P-2 HVAC, CU230P-2 DP, CU230P-2 CAN
136
Operating Instructions, 01/2011, FW 4.4, A5E02430659B AD
6.2.3.4
Baud rates and mapping tables
Permissible baud rates and telegram delay
The Modbus RTU telegram requires a pause 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]).
A character delay time is also permitted between the individual bytes of a frame. Maximum
duration: Processing time for 1.5 bytes (can be set via p2024[1]).
Table 6- 29 Baud rates, transmission times, and delays
Baud rate in bit/s (p2020) Transmission time per
character (11 bits)
Minimum pause
between two
telegrams (p2024[2])
Maximum pause
between two bytes
(p2024[1])
4800
2.292 ms
≥ 8.021 ms
≤ 3.438 ms
9600
1.146 ms
≥ 4.010 ms
≤ 1.719 ms
19200 (factory setting)
0.573 ms
≥ 1.75 ms
≤ 0.859 ms
38400
0.286 ms
≥ 1.75 ms
≤ 0.75 ms
57600
0.191 ms
≥ 1.75 ms
≤ 0.556 ms
76800
0.143 ms
≥ 1.75 ms
≤ 0.417 ms
93750
0.117 ms
≥ 1.75 ms
≤ 0.341 ms
115200
0.095 ms
≥ 1.75 ms
≤ 0.278 ms
187500
0.059 ms
≥ 1.75 ms
≤ 0.171 ms
Note
The factory setting for p2024[1] and p2024[2] is 0. The particular values are pre-assigned
depending on the protocol selection (p2030) or the baud rate.
Modbus register and Control Unit parameters
Since the Modbus protocol can only handle register or bit numbers for addressing the
memory, assignment to the appropriate control words, status words and parameters is
performed on the slave side.
The converter supports the following addressing ranges:
Addressing range
Remark
40001 … 40065
Compatible with Micromaster MM436
40100 … 40522
Содержание SINAMICS G120 CU230P-2
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