Bosch Rexroth EFC 3600, Operating Instructions Manual, Page: 175 / 238

● The address 0 is reserved as broadcast address.
● All slave nodes must recognize the broadcast address for writing function (no need
of reply).
● The master node has no specific address, only the slave nodes must have an ad‐
dress (from 1 ~ 247).
For RTU transmission mode, three type character formats are shown below:
● 1 start bit, 8 data bits, 1 stop bit, no parity;
● 1 start bit, 8 data bits, 1 stop bit, even parity;
● 1 start bit, 8 data bits, 1 stop bit, odd parity;
● 1 start bit, 8 data bits, 2 stop bits, no parity.
And the character or byte is sent in this order (from left to right):
<-Least Significant Bit (LSB) Most Significant Bit (MSB)->
With parity checking
Start 1 2 3 4 5 6 7 8 Parity Stop
Without parity checking
Start 1 2 3 4 5 6 7 8 Stop Stop
Fig.13-2: RTU transmission mode
Message frames are separated by a silent interval of at least 3.5 character times. The
entire frame must be transmitted as a continuous stream of bytes. If the interval of two
separated frames is less than 3.5 character times, then the slave address of second
frame will be treated as the part of first frame by mistake, due to the confusion of the
frames, the CRC check will fail and lead to communication fault. If a silent interval of
more than 1.5 character times occurs between two bytes, the message frame is de‐
clared incomplete and should be discarded by the receiver.
13.2.2 Interface
The communication interface of EFC 3600 frequency converters is shown as below:
Fig.13-1: Communication interface
DOK-RCON03-EFC-3600***-IT01-EN-P
Rexroth Frequency Converter EFC 3600 Bosch Rexroth AG
Communication Protocols
173/235