Omron V720S Series, Руководство по эксплуатации

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Communications Command Section 5-3
5-15
Caution From Page FD to Page FE is a system area for write-protect and
QUIET/EAS settings. Depending on the content of write data, a Tag may
become write-protected or inaccessible, so be sure to understand these
pages fully before use.
It is strongly recommended that you use a system command to write in
these pages (refer to 5-4) rather than using the write command.
5-3-4 Special Read (RD): For I.CODE1 Mode Only
When there is only a single Tag in the communications area, this command enables to read data
from the Tag faster than a usual Read.
<Command Format>
STX Node No..
Command code
“RD”
Communi-
cations
method
Data
type
Setting
Tag
No.
First read
page
No. of read
pages
ETX BCC
1 2 2 2 1 1 2 2 1 1
Communications
method
Specifies the communications method with a Tag.
UT: Special Read Trigger
UA: Special Read Auto
UR: Special Read Repeat
* For details, refer to 5-8 Communications Methods
Data type Specifies whether the read data is represented in ASCII or HEX.
A : ASCII code
H : HEX code
* For details, refer to 5-9 Data Type
Tag No. setting Set the number of Tags which communicate simultaneously.
* For details, refer to 5-10 Tag No. setting.
Specification range: 0 to 7
First read page Specifies the first page in hexadecimal to read from the Tags.
Specification range: FB to 04h (when Block 4 for a Philips product is used
as the user memory, refer to 2-4 of Section 2 Memory Map of Tag)
No. of read pages Specifies the number of pages from which data is read in hexadecimal.
Specification range: 01 to 10
<Response Format>
STX Node No..
Retry
flag
Command code
“RD”
Response
code
“00”
Read data ETX BCC
1 2 1 2 2 As specified 1 1
Response code 00:normal completion
For other response codes, refer to 5-2-4 Response code List.
Read data Indicates data having read from the Tag. The number of characters of the
data is as follows.
ASCII Code: No. of write pages x 4
HEX code: No. of write pages x 8
Note This Special Read (RD) Command enables you to read from multiple Tags,
however, unlike the read command (5-3-1) of multi-communications method,
this Special Read Command does not execute anti-collision processing (a
collision avoidance processing against the responses from a Tag). Thus
when a collision (conflict between responses) occurs, it will be unable to read
data from a Tag. To read data from a Tag, the host must retry Repeat Com-
mand. When there are a few Tags, the Special Read Command has an ad-
vantageous communication speed rather than multi-command does even if it
executes Retry processing. The command works in I.CODE1 mode only, and
ISO mode is not available.
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