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Program Protection Section 6-7
6-7-2 Write Protection
Write-protection
Using the DIP Switch
The user program can be write-protected by turning ON pin 1 of the CPU
Unit’s DIP switch. When this pin is ON, it won’t be possible to change the user
program or parameter area (e.g., PLC Setup and routing tables) from the CX-
Programmer. This function can prevent the program from being overwritten
inadvertently at the work site.
It is still possible to read and display the program from the CX-Programmer
when it is write-protected.
CPU Unit DIP Switch
Confirming the User Program Date
The dates the program and parameters were created can be confirmed by
checking the contents of A90 to A97.
Auxiliary Area Words
Pin Name Settings
SW1 User Program Memory Write Protection ON: Protected
OFF: Not protected
Name Address Description
User Program
Date
A90 to A93 The time and date the user program was last over-
written in memory is given in BCD.
A90.00 to A90.07 Seconds (00 to 59 BCD)
A90.08 to A90.15 Minutes (00 to 59 BCD)
A91.00 to A91.07 Hour (00 to 23 BCD)
A91.08 to A91.15 Day of month (01 to 31 BCD)
A92.00 to A92.07 Month (01 to 12 BCD)
A92.08 to A92.15 Year (00 to 99 BCD)
A93.00 to A93.07 Day (00 to 06 BCD)
Day of the week:
00: Sunday, 01: Monday,
02: Tuesday, 03: Wednesday,
04: Thursday, 05: Friday,
06: Saturday
Parameter Date A94 to A97 The time and date the parameters were last overwrit-
ten in memory is given in BCD. The format is the
same as that for the User Program Date given above.
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