5-6
Section
Communications Commands
81
5-6-4 SUBTRACT: SB
The data in the memory of the ID Tag is treated as hexadecimal data, to which
SB data is subtracted.
Command Frame Structure
STX
Node No.
Command
code
SB
Commu-
nications
Chan-
nel
First address
of subtract
area
No. of bytes in
subtract area
ETX
BCC
Subtract data
Specified
quantity
1
2
2
2
1
2
2
1
1
Communications
Specify the communications method with the Tag.
ST:
Single trigger
FR: FIFO repeat
SA: Single auto
ME: Multi-trigger
SR: Single repeat
MR: Multi-repeat
FT:
FIFO trigger
L
j
: Selective access
FA: FIFO auto
(
j
=
*
for Tag detect, ID number 0 to F for Tag specify.)
Channel
Always 1.
First address of subtract
area
The first address of data to be subtracted in hexadecimal.
Setting range: 00h to EFh
No. of bytes in subtract
area
The number of data bytes to be subtracted in hexadecimal.
Setting range: 01h to 08h
Subtract data
Data to be added to the ID Tag.
The number of SB data characters is twice as large as the number of SB area bytes.
Response Frame Structure
STX
Node No. Retry
Flag
Command
code
SB
Response
code
75
ETX
BCC
Results data
Specified
quantity
1
2
1
2
2
1
1
Response Frame Structure for Selective Access Function (Excluding Detection Completed Response)
STX
Node No. Retry
Flag
Command
code
SB
Response
code
75
ETX
BCC
Results data
Specified
quantity
1
2
1
2
2
1
1
ID
No.
1
Response code
75:
Normal response with a result not below 0.
76:
Normal response with a result below 0.
Refer to 5-12 List of Response Codes for other response codes.
ID No.
This is the temporary ID number assigned to the Tag by the Controller for the selective
access function. Normally the ID No. is between 0 and F, but the Controller will return ID
number “X” for the 17
th
and later Tags if the max. number of Tags (16) was exceeded.
Results data
The result of the subtraction of data is sent. If the result is below 0, the previous data is
sent.
Note
1. Make sure that the SB area is within a single page, otherwise a command
error will result.
2. Make sure that the specified data is within the memory capacity of the ID
Tag.
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