Presentation Of The Question And Answer Frames; Checking Received Messages On The Slave Side - MGE UPS Systems SineWave JBUS Manuel D'installation Et D'utilisation

JBUS protocol
presentation of the
question and answer
frames
checking received
messages on the slave side
After the master sends a request
containing the slave address, the
function code and data, it computes the
CRC and sends it as the check word
(CRC 16).
When the slave receives the request, it
stores the message in memory and
calculates the CRC 16 to compare it to
the received CRC 16.
10
(cont.)
request
1 byte
slave address
(1 to FF)
this function code selects one of
4 possible commands
available on SineWave™
- function 3 : read n output or internal words
- function 4 : read n input words
- function 6 : write one word
- function 16 : write n words
response
slave address
(1 to FF)
1 byte
master
SineWave™ JBUS communication system installation: E-51027160XT/AC
information requested: bit/word
address, bit/word value,
bit/word number.
1 byte
information
function
code
n bytes
values of bits or words read
values of bits or words written
number of bits or words
function data
code
1 byte n bytes
slave
slave address
function
data
CRC 16
CRC 16 comparison
2 bytes
check word
when the message is
received, the slave reads
the check word and accepts
or refuses the message
CRC
check word
2 bytes
CRC 16
computation
MGE UPS SYSTEMS