Omron V600 User Manual page 108

Section 4
Functions
Data Carrier Life after Low Battery Signal Occurs
After a battery-low signal is sent, the Data Carrier can be used for approximately one month in the
normal operating state. The Data Carrier should be replaced, however, as soon as possible.
The SRAM Data Carrier (except the V600-D2KR16) is equipped with a thionyl chloride lithium battery. A characteristic
of the thionyl chloride lithium battery is that the internal resistance of the battery increases when the battery is left
unused for several months. If this occurs and a Data Carrier battery-low check is performed, a low battery response
may be returned regardless of whether battery life still remains. This is a result of the increased resistance within the
battery, and is not due to the battery life expiring. If a Data Carrier has been left for several months after purchase with-
out being used, use the read operation for approx. 10 minutes to activate the battery before use. (Current will flow in the
battery and resistance in the battery will return to normal as a result of activating the battery. The life of the battery will
hardly be affected.)
When using V600-D2KR16 Data Carriers with replaceable batteries, the Data Carrier can be used for
approximately two weeks in the normal operating state. The battery should be replaced, however, as
soon as possible.
•EEPROM Data Carrier (without Battery)
The OVERWRITE COUNT CONTROL command (MDS) can determine whether the overwrite count
for the EEPROM Data Carrier has been exceeded. By executing the OVERWRITE COUNT
CONTROL command, the number of overwrites is decremented from the data in the specified
overwrite count control area, and whether the data has exceeded the limits is determined.
The overwrite count control area consists of 3 bytes
from the start address. The decrement value from the
overwrite count is written in this area, and if this value
is 0 (00H) an end code 76 will be given as a warning.
Therefore, to enable control of the number of
overwrites, the maximum number of overwrites must
be written to the overwrite count control area
beforehand.
The user-specified number of overwrites can be set to
up to 16,700,000. The number of overwrites in the
specifications for EEPROM Data Carriers, however, is
300,000 overwrites (0493E0H) at 40 ° C max., so be
sure to set the number of overwrites to 300,000 or
lower.
The number of overwrites is controlled using hexadecimal
values, and can be read using the READ command.
If the control area data is already 0, 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 REF OVERWRITE COUNT CONTROL (MDS).
RFID System
106
User's Manual
p.87
Upper digit
Area start address
Middle digit
Lower digit
3 bytes