BECKHOFF BC7300 - Manual (Page 35)

BC7300 35
EXAMPLE Query
Byte Name Example RTU ASCII
Start frame „:“ 0x3A
Slave address 11 0x0B „0B“ 0x30, 0x42
Function code 8 0x08 „08“ 0x30, 0x38
Subfunction high 0 0x00 „00“ 0x30, 0x30
Subfunction low 0 0x00 „00“ 0x30, 0x30
Data high 2 0x02 „02“ 0x30, 0x32
Data low 3 0x03 „03“ 0x30, 0x33
Error Check
LRC / CRC
0xA1
0xC0 „E8“ 0x45, 0x38
End of frame t1-t2-t3 CRLF 0xD, 0xA
Response
Byte Name Example RTU ASCII
Start frame „:“ 0x3A
Slave address 11 0x0B „0B“ 0x30, 0x42
Function code 8 0x08 „08“ 0x30, 0x38
Subfunction high 0 0x00 „00“ 0x30, 0x30
Subfunction low 0 0x00 „00“ 0x30, 0x30
Data high 2 0x02 „02“ 0x30, 0x32
Data low 3 0x03 „03“ 0x30, 0x33
Error Check
LRC / CRC
0xA1
0xC0 „E8“ 0x45, 0x38
End of frame t1-t2-t3 CRLF 0xD, 0xA
Echoes a query (Sub-Function 0)
Sub-function 0 causes the data that is sent to the slave by the master to be
returned.
Bus Coupler Reset (Sub-Function 1)
Sub-function 1 re-initialises the BC7300. Error counters are reset, and the
coupler executes a self-test. No telegrams are either received or sent while
the coupler is being reset.
Sub-function
Data field (query) Data field (response)
00 01 00 00 00 00
Delete All Counter Contents (Sub-Function 10)
Calling this sub-function deletes the contents of all error counters in the
coupler.
Sub-function
Data field (query) Data field (response)
00 0B 00 00 Echo Query Data
Bus Communication Error Counter (Sub-Function 11)
Returns the number of faulty communications.
Sub-function
Data field (query) Data field (response)
00 0C 00 00 CRC error counter
Error Answer Counter (Sub-Function 13)
This counter contains the number of error answer telegrams that the
coupler has sent.
Sub-function
Data field (query) Data field (response)
00 0D 00 00 Error Answer Counter