innoaloe

CP1L Using Password without Battery Installed

1 post in this topic

Hi everyone,

recently we got a complain about UM password protection in the CP1L. So our user intended to apply password to a CP1L PLC which doesn't have battery installed. They were testing to turning off the PLC for about a week. In the 8th day, they turned it on again and tried to upload the program from the PLC. But after they input the password, and error shows up which indicates whether the password is wrong, or already inputted wrong 5 times in a row.

Further checking shows that A99.12 memory was turned on which indicates that wrong password has been inputted 5 times. This was not the actual case since we make sure no one was using the PLC in those 7 days.

A99.12 by its nature is not a non-retain memory. Is it possible that during Power On, the memory is unstable that it turned On by itself? I know it can be the case on some areas like DM / WR and also the RTC memory. And since A99.12 is a Read-Only memory, we cannot use P_First_Cycle to ensure it's turned Off as what we used to do with A500.12 (Inhibit Output).

Currently I'm testing it by myself, for 3 days had left the PLC Powered Off. If anyone had inputs about this please advice. Thank you

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