Balluff BIS Series, Руководство пользователя

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The BCC block check is formed as an EXOR of the serially transmitted binary characters of
the telegram block. Example: Read 128 bytes starting at address 13.
The command line without BCC is: 'L 0013 0128 10'
The BCC is formed: 'L = 0100 1100 EXOR
0 = 0011 0000 EXOR
0 = 0011 0000 EXOR
1 = 0011 0001 EXOR
3 = 0011 0011 EXOR
0 = 0011 0000 EXOR
1 = 0011 0001 EXOR
2 = 0011 0010 EXOR
8 = 0011 1000 EXOR
1 = 0011 0001 EXOR
0' = 0011 0000 EXOR
Block check result: BCC = 0100 0100 = 'D'
If necessary, termination using block check BCC can be replaced with a special ASCII charac-
ter. This is:
– Carriage Return 'CR'
Example: Read 128 bytes starting at address 13.
The command line with 'CR" as a terminator is then: 'L 0013 0128 10 CR'
Variant for
terminating with 'CR'
instead of BCC
Function Description BIS M-81_ / PC
Reading / Writing over the serial interface
BCC Block Check
M-81_854610_E_0703.p65
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Data within angle brackets are control characters.
Values inside apostrophes represent the respective character(s) in ASCII code.
1) The Quit command is not permitted at this point.
2) <ACK> '0' is returned as acknowledgement if there is no error, or <NAK> + 'Error No.' if an error occurs.
Read from data carrier with block size select
Write to data carrier with block size select
Task Data flow Com-
mand Start
address of
first byte to
be set Number of
bytes to be
sent End Acknow-
ledge 2)
Start
trans-
mission Data (from start
address to start
a no. of
bytes) End Acknow-
ledge 2)
Read from host
system to
BIS 'L' A3 A2 A1 A0
'0 0 0 0'
to
memory
capacity -1
L3 L2 L1 L0
'0 0 0 1'
to
memory
capacity
'1' '0'
BCC
or
'CR' <STX>
from BIS
to host
system <ACK>'0'
or <NAK>
+ Error-No. D1 D2 D3 ... Dn BCC
or
'CR'
1)
Write from host
system to
BIS 'P' A3 A2 A1 A0
'0 0 0 0'
to
memory
capacity -1
L3 L2 L1 L0
'0 0 0 1'
to
memory
capacity
'1' '0'
BCC
or
'CR' <STX> D1 D2 D3 ... Dn BCC
or
'CR'
from BIS
to host
system <ACK>'0'
or <NAK>
+ Error-No. <ACK>'0'
or <NAK>
+ Error-No.
1) 1)
Telegram Structure and Examples
Reading / Writing over the serial interface