JBUS protocol (continued)

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.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

request

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

slave address

 

 

0B

 

 

CRC 16

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

response

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

slave address

 

 

0B

 

 

0

 

slave

 

 

CRC 16

 

 

 

 

 

 

counter word

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1 byte

 

 

1 byte

2 bytes

 

2 bytes

2 bytes

 

 

 

 

 

 

 

 

 

 

 

 

 

 

If the master counter equals the

 

 

If the master counter is one higher

slave counter, the slave executed

 

than the slave counter, the slave

the command sent by the master.

 

did not execute the command sent

 

 

 

 

 

 

 

 

 

by the master.

 

 

Function 15: writing n consecutive bits

request

slave adress

0F

address of the first bit

number of bits

number of bytes

bit data

CRC 16

1 byte

1 byte 2 bytes

 

2 bytes

 

 

1 byte

 

n bytes

 

 

2 bytes

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

réponse

 

2 X 1968

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1 N 246

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

last bit of

 

first bit of

last bit of

first bit of

first byte

 

first byte

byte N

byte N

 

first byte

 

N bytes

 

 

 

 

 

response

 

 

 

 

 

 

 

 

 

slave address

0F

address of the first bit

number of bits

CRC 16

1 byte

1 byte

2 bytes

2 bytes

2 bytes

 

 

1

X 1968

 

Note: if the slave address is 0, all units execute the write command without sending a response.

Page 12 - 6739389EN/FB

Page 12
Image 12
APC 6000 user manual Function 11 reading event counters, Function 15 writing n consecutive bits