
BIS C-87_
Handheld Programmer
18
In order to ensure data integrity, data transfer between the data carrier and processor must be
monitored using a check procedure.
The factory default setting in the Handheld Programmer is for double reading with comparison.
Alternately the CRC_16 data check can be selected.
Here a check code is written to the data carrier that always allows the data to be checked for
integrity.
Which procedure should be used depends on how the Identification System is used.
Note
Mixed operation of both check procedures is not possible!
The following table provides an overview of the advantages of the respective check procedure.
CRC_16 data check
Double reading
Data integrity even during the non-active
phase (data carrier outside the
read/write head zone).
No user bytes are sacrificed for storing a
check code.
Shorter read time – page is read once.
Shorter write time – no check code is written.
Data read from a data carrier can be saved under a file name or saved files can be loaded.
Note
User data are saved by default in a RAM-based folder. The data in this RAM folder are
lost if the main battery pack and backup battery pack are fully drained or if the device
is restarted cold. The safest place to store the data is an SD or MMC memory card
(flash disk).
Start address of the data on the
data carrier
No. of bytes
Data carrier data
4 bytes
4 bytes
Max. 184 bytes
Example:
Data carrier file starting at Address 75 with 16 bytes of data in ASCII format.
Data: ABCDEFGHIJKLMNOP
Contents of data carrier file:
00750016ABCDEFGHIJKLMNOP
4.4 Data integrity
Data check
4.5 Files
File format
Basic knowledge
4
Содержание BIS C-87 Series
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