Configuring the fieldbus
6.2 Communication via RS485
Inverter with CU240B-2 and CU240E-2 Control Units
124 Operating Instructions, 01/2011, FW 4.4, A5E02299792B AB
6.2.2.2 Basic settings for communication
Parameter Description
P0015 = 21 Macro drive unit
Selecting the I/O configuration
p2020 Value
4
5
6
7
8
9
10
11
12
13
Baud rate
2400
4800
9600
19200
38400
57600
76800
93750
115200
187500
p2022 Fieldbus interface, USS PZD count
Setting the number of 16-bit words in the PZD part of the USS telegram
Fieldbus interface, USS PKW count
Setting the number of 16-bit words in the PKW part of the USS telegram:
p2023
Value
0
3
4
127
PKW count
PKW 0 words
PKW 3 words
PKW 4 words
PKW variable
p2040 Fieldbus interface, monitoring time [ms]
Setting the monitoring time to monitor the received process data via fieldbus. If no
process data are received within this time, an appropriate message is output
Additional information and parameters are provided on the following pages.
6.2.2.3 Structure of a USS telegram
A USS telegram comprises a sequence of characters, which are sent in a defined sequence.
Every character within the telegram comprises 11 bits. The sequence of characters of a USS
telegram is shown in the following diagram.
6WDUWGHOD\ 866IUDPH
n net data
Final
information
Header information
ELWGDWD
%LW
VWRS
%LW
3HYHQ
%LW
6WDUW
STX LGE ADR 1. 2. : : : n BCC
Figure 6-5 Structure of a USS telegram
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