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Page 12 - 6739389EN/FB
Function 11: reading event counters
The master and each slave have
one event counter.
This counter is incremented each
time a frame is received and
interpreted correctly by the slave
(except for function 11 itself).
A correctly transmitted message
increments the counter. If the slave
sends an exception response, the
counter is not incremented.
The master can read the counter to
determine whether or not the slave
correctly interpreted the command
(incremented the counter or not).
These functions can be used to
diagnose the data exchange taking
place between master and slaves.
If the master counter equals the
slave counter, the slave executed
the command sent by the master.
If the master counter is one higher
than the slave counter, the slave
did not execute the command sent
by the master.
Function 15: writing n consecutive bits
request
slave address 0B
CRC 16
response
slave address
1 byte
1 byte 2 bytes 2 bytes 2 bytes
CRC 160B
0
slave
counter word
réponse
request
0F
slave adress
CRC 16
1 byte
1 byte
2 bytes
2 bytes
1 byte n bytes 2 bytes
slave address
response
Note: if the slave address is 0, all units execute the write command without sending a
response.
1 byte
2 bytes1 byte 2 bytes 2 bytes
0F CRC 16
1 X 1968
last bit of
first byte
last bit of
byte N
first byte
N bytes
1 N 246
2 X 1968
bit data
number of bits
address of
the first bit
first bit of
first byte
first bit of
byte N
number
of bits
number
of bytes
address of
the first bit
JBUS protocol (continued)