Data Retention on EEPROM?

Ok, quick question. I've got a SLC 5/03. One of the data tables is used to track "all time highs" of certain variables. In other words, the highest that a particular set of integers has ever been. Everything works fine, but when the power is cycled, which doesn't happen very often but happens nonetheless, it resets all of these numbers. The EEPROM loads the stored program (along with the data files). So, I'm not getting the true "highest" values if a new value has been set since the EEPROM was saved.

Is there a way to stop this? I've read about data file protection, but I don't really know if this is what I'm looking for. I just want to NOT lose my "all time highs" with a power cycle. Any suggestions? And yes, all of the values I want to keep are in the same data file.

Ok, so with all of the gurus on here, no one knows the answer to this question??? I'm not buying it. Where's Ron Beaufort when you need him!?!? (Or Okie, Mickey, Peter...the list goes on),

shoelesscraig said:

Ok, quick question. I've got a SLC 5/03. One of the data tables is used to track "all time highs" of certain variables. In other words, the highest that a particular set of integers has ever been. Everything works fine, but when the power is cycled, which doesn't happen very often but happens nonetheless, it resets all of these numbers. The EEPROM loads the stored program (along with the data files). So, I'm not getting the true "highest" values if a new value has been set since the EEPROM was saved.

Is there a way to stop this? I've read about data file protection, but I don't really know if this is what I'm looking for. I just want to NOT lose my "all time highs" with a power cycle. Any suggestions? And yes, all of the values I want to keep are in the same data file.

Click to expand...

I think this will work. If you are not saving the Data to an entirely separate Data Table, then create a new Data Table and modify your program to save your highest values to it. Under the Data File Properties, at the bottom of the dialog, there is a Protection section. Check Memory Module. My understanding is this will protect your Data during a normal Memory Module Loads. However, it will not protect it if the Load is caused by a Memory Corruption. All these changes must be done Offline and Downloaded to the PLC.

Search for Data File Protection in the SLC500 Help.

Stu.....

Thanks Stu. I'll go ahead and try doing what you said. It was my understanding that you had to either click "static" or "constant" as your protection type for that data file, and selecting "memory module" just added the static or constant protection to the EEPROM as well. But, I may be misunderstanding. I'll try to post what I find.

Another thing you may want to do is only load from EEPROM on a memory corruption. Do this by setting S:1/10 and leave the other EEPROM bits at zero.

Then it should very rarely happen, and you can monitor the state of S:5/8 (as long as it was saved with a 0 there) to detect when an EEPROM load has occurred.

OkiePC said:

Another thing you may want to do is only load from EEPROM on a memory corruption. Do this by setting S:1/10 and leave the other EEPROM bits at zero.

Then it should very rarely happen, and you can monitor the state of S:5/8 (as long as it was saved with a 0 there) to detect when an EEPROM load has occurred.

Click to expand...

Good idea. This may be the ticket...