SEW MOVIDRIVE MDX60B, User Manual

Page: 27 / 144

Manual – MOVIDRIVE® MDX60B/61B Communication and Fieldbus Unit Profile
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MOVILINK® protocol via RS485 transmission method
Serial Interfaces of MOVIDRIVE® B
The following figure shows the structure of a request telegram with the standard PDU
types. The associated response telegram has the same structure except for the SD2
start character.
Block check character
Transmission
reliability Transmission reliability with the MOVILINK
®
protocol is increased by a combination of
character parity and block parity. The parity bit is set for each character of the telegram
in such a way that the number of binary ones including the parity bit is even-numbered.
Block parity provides for additional reliability and means that a block check character
(BCC = Block Check Character) is added to the telegram. Each bit of the block check
character is set in such a way that the result is an even parity for all information bits of
the same value of the telegram character. In programming, the block parity is imple-
mented by EXORing all telegram characters. The result is entered in the BCC at the end
of the message. The block check character itself is also ensured with the even character
parity.
01493BEN
...Idle... SD1 ADR TYP PDU BCC
TYP 1/129
TYP 3/131
TYP 5/133
TYP 6/134
TYP 0/128
TYP 2/130
TYP 4/132
PD1
PD1
PD1
PD1
PD2
PD2
PD1
PD1
PD2
PD2
PD3
PD3
8 byte parameter channel
8 byte parameter channel
8 byte parameter channel
8 byte parameter channel