Connection to a fieldbus
6.4 Communication via RS485
Inverter with CU240B-2 and CU240E-2 Control Units
134 Operating Instructions, 07/2010, FW 4.3.2, A5E02299792B AA
LGE
LGE specifies the number of bytes that following in the telegram. It is defined as the sum of
the following bytes
● Net data
● ADR
● BCC
The actual overall telegram length is two bytes longer because STX and LGE are not
counted in LGE.
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
Mirror Send
5 address bits
● Bit 5 is the broadcast bit.
Note
The Broadcast function is not supported in the current software version.
● Bit 6 = 1 indicates a mirror telegram.
The node address is evaluated and the addressed slave returns the telegram to the
master unchanged.
Bit 5 = 0, bit 6 = 0 and bit 7 = 0 indicate normal data communication for devices. The node
address (bit 0 to bit 4) is evaluated.
BCC
BCC (Block Check Character). It is an exclusive OR checksum (XOR) over all telegram
bytes with the exception of the BCC itself.
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