64
Data Carrier Life Check
Section 5-6
4.
If the start address exceeds the end address (start address > end ad-
dress), the areas from the start address to the end of the Data Carrier
memory area (address 07FF (hex)) and from address 0006 (hex) to the
specified end address will be write-protected.
Clearing Write Protection
To clear write protection, set bit 7 of address 0002 (hex) to 0. Write protection
will be cleared and the end address and start address set in addresses 0002
(hex) to 0005 (hex) will be disabled. When clearing write protection, write only
to the write protection setting area (4 bytes starting from address 0002). If
other addresses are written to, a write protection error will occur and write pro-
tection will not be cleared.
5-6
Data Carrier Life Check
The method used to control the life of the Data Carriers depends on the Data
Carrier memory type (SRAM or EEPROM).
For SRAM (built-in battery) Data Carriers, the life of the battery is controlled.
For EEPROM (battery-free) Data Carriers, the number of writes is controlled
(100,000 writes or user setting).
5-6-1
EEPROM (Battery-free) Data Carriers
The Number of Writes Control command can be used to manage the life of
EEPROM (battery-free) Data Carriers. The end of the life of a Data Carrier is
detected by using the Number of Writes Control command to detect when the
number of times a EEPROM (battery-free) Data Carrier has been written
exceeds either 100,000 writes or a specified number of writes.
There are two ways to manage the number of writes. One is to add to the
number of writes and then detect when the total exceeds 100,000 writes. The
other is to subtract from a user-specified number of writes and then detect
when the specified value has been exceeded (i.e., when 0 is reached).
Number of Writes Control 1 (Life Control = Preset Number of Writes)
The Number of Writes Control Area consists of 3 bytes from the start address.
The Number of Writes Control command is executed with an Add specifica-
tion. The specified numbers of writes are added and the total is written to the
control area.
When the value in the number of writes control area exceeds the preset num-
ber of writes (100,000 writes), the Status Flag (word (n + 8), bit 04) in the
Address (hex)
0000
0006
07FF
End address
Start address
Summary of Contents for CJ - 12-2004
Page 2: ...SYSMAC CS CJ Series ID Sensor Units Operation Manual Revised December 2004...
Page 3: ...iv...
Page 11: ...xii...
Page 55: ...36 Connections and Wiring Section 3 4...
Page 69: ...50 I O Data Allocations Section 4 3...
Page 91: ...72 Data Check Section 5 7...
Page 141: ...122 Sample Programming Appendix B...
Page 147: ...128 Revision History...