5-3
Using an EEPROM or EPROM
TI545/TI555 System Manual
The EEPROM stores the user program including the following:
•
Relay ladder logic (RLL).
•
K memory.
•
U memory.
•
S memory (PID loops, analog alarms, and SF programs).
•
Memory configuration.
•
I/O configuration.
•
Password , if installed.
•
Scan configuration.
After storage in the EEPROM, this data is saved even if power is cycled
without a backup battery. However, other data in memory will be lost if you
do not have a backup battery.
NOTE:
To help ensure that the data listed above is saved, the total user
memory space to be stored in the EEPROM must not exceed 126K bytes or
254K bytes. If the total user memory (not system memory) space occupied
by these areas is greater than 126K bytes or 254 K bytes, no data is saved.
The error message,
OPERATION FAILED
, is displayed on the screen if the
user memory exceeds the applicable size when attempting to save the data.
If your operating program does not change, you can store it permanently on
an EPROM. You can use an EPROM copier to copy your program from an
EEPROM to an EPROM. (The EPROM cannot be programmed in the CPU.)
This is a cost-effective method for creating duplicate copies if you have
additional CPUs running the same program.
Using an EPROM