67
RFID System
Operation Manual
Section 4 Data Carrier Service Life Detection
Section 4
Function
■ MDL Command
The overwrite count control area consists of 3 bytes
from the start address. The incremented value of the
overwrite count is written in this area, and if this value
is 100,000 (0186A0H) an end code of 76 will be
returned as a warning.
The number of overwrites is controlled using hexadeci-
mal values.
The current value can be read using the READ com-
mand.
If the control area data is already 100,000, the control
area value will not be refreshed, and only a warning will
be returned as a response.
When the refresh count is set as 00H, the count will not be updated, and only an overwrite count check
will be performed.
Set the start address to between @@@0H and @@@5H or between @@@8H and @@@DH. If the start address is set
between @@@6H and @@@7H or between @@@EH and @@@FH, an address error (error code: 7A hexadecimal) will
be returned as the end code.
For details on command format, refer to MANAGEMENT DATA SUBTRACTION/LIMIT (MDS/MDL).
p.118
■ Application Example for MANAGEMENT DATA LIMIT (MDL)
Using the Three Bytes from Address 0010H as the Overwrite Count Area
Do not use both the MDS and MDL commands for the same Data Carrier. Doing so will prevent overwrite management.
Overwrite Life of Data Carriers without Batteries
Number of overwrites with an ambient temperature between the minimum temperature and 70C: 100,000
Number of overwrites with an ambient temperature between the minimum temperature and +40C: 300,000
1. The overwrite count area is cleared.
“WTH10010000000” is executed.
2. Enter an overwrite count of 4. “MDL1001004”
3. Enter an overwrite count of 5. “MDL1001005”
The value will be added, making the count 9.
4. The accumulated count is 100,000 times.
When “MDL1001000” is executed, the
“MD76” will be returned (overwrite count
exceeded).
3 bytes
Area start address
Upper digit
Middle digit
Lower digit