SEW MOVIDRIVE MDX60B, User Manual

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Manual – MOVIDRIVE® MDX60B/61B Communication and Fieldbus Unit Profile
4
MOVILINK® protocol via RS485 transmission method
Serial Interfaces of MOVIDRIVE® B
4.3 MOVILINK
®
protocol via RS485 transmission method
4.3.1 Transmission method
An asynchronous, serial transmission method is used which is supported by the UART
modules common in digital technology. This means the MOVILINK
®
protocol can be
implemented in nearly all controllers and master modules.
Characters Each character in the MOVILINK
®
protocol consists of 11 bits and is structured as fol-
lows:
• 1 start bit
• 8 data bits
• 1 parity bit, completing for even parity (even parity)
• 1 stop bit
Each transmitted character begins with a start bit (always logical 0). The start bit is fol-
lowed by 8 data bits and the parity bit. The parity bit is set in such a way that the number
of logical ones in the data bits including the parity bit is even-numbered. The last bit of
a character is a stop bit, which is always set to logical level 1. This level remains on the
transmission medium until a new start bit signals the transmission of another character.
Transmission
rate and
transmission
mechanisms The transmission rate is 9600 baud or 57.6 kBaud (via XT only). The communications
link is monitored by the master and the inverter itself. The master monitors the response
delay time. The inverter monitors the reception of cyclic request telegrams of the master.
Response delay of
the master A response delay is usually programmed on the higher-level master system. The
response delay is the interval between the time when the last character of the request
telegram is sent (BCC) and the time when the response telegram is sent (SD2). The
maximum permitted response delay interval is 50 ms. A transmission error has occurred
if the inverter does not respond within this interval. Check the interface cable and the
coding of the sent request telegram. Depending on the application, the request telegram
should now be repeated and the next inverter be addressed.
Start delimiter
(idle) To interpret a character as start delimiter (02
hex
or 1D
hex
), it must be preceeded by a
pause of at least 3.44 ms.
Character delay The interval between the time when a character of a telegram is sent must be shorter
than the time preceeding the start delimiter (which means max. 3.43 ms). Else, the
telegram is invalid.
64767AEN
0 1 2 3 4 5 6 7
LSB MSB even
St
ar
t
Parity
St
op
St
ar
t
Character
8 data bits