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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
122
Operating Instructions, 01/2011, FW 4.4, A5E02430659B AD
ADR
The ADR range contains the address of the slave node (e.g. of the inverter). The individual
bits in the address byte are addressed as follows:
7
6 5 4 3 2 1
0
Special
telegram
Broadcast
bit
Mirror
telegram
5 Address bits
●
Bit 5 broadcast bit
Bit 5 = 0: normal data exchange. Bit 5 = 1: Address (bits 0 … 4) is not evaluated (is not
supported in SINAMICS G120!).
●
Bit 6 mirror telegram
Bit 6 = 0: normal data exchange. Bit 6 = 1: The slave returns the telegram unchanged to
the master. Is used to test the bus connection.
●
Bit 7 special telegram
Bit 7 = 0: normal data exchange. Bit 7 =1 to transfer telegrams that require a net data
structure different from the device profile.
BCC
BCC (Block Check Character). It is an exclusive OR checksum (XOR) over all telegram
bytes with the exception of the BCC itself.
6.2.2.4
User data range of the USS telegram
The user data range of the USS protocol is used to transmit application data. This comprises
the parameter channel data and the process data (PZD).
The user data occupy the bytes within the USS frame (STX, LGE, ADR, BCC). The size of
the user data can be configured using parameters p2023 and p2022. The structure and
sequence of the parameter channel and process data (PZD) are shown in the figure below.
3.(
,1'
3:( 3:(
3:(P
3
3
3
3
3
Q
3.: 3.: 3.: 3.:
3.:P 3='
3='
3='\
67:
=6:
+6:
+,:
3
3
3='
3
3
3='
67:
=6:
S
S
S
S
S
S YDULDEOHOHQJWK
3URFHVVGDWD3='
3.:3='VWUXFWXUH
'DWDE\WH
3URWRFROGDWD
3DUDPHWHUFKDQQHO3.:
3URWRFROZRUGV
Figure 6-6
USS user data structure
Содержание SINAMICS G120 CU230P-2
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