PLC loose program after power outage or if PLC gets turned off

The program has two targets. one is running on RX3i and other one is quickpanel (QP view 15''). Every time, when we have power outage problem or the machine gets turned off, the PLC loose the program and we have to download the target program into the controller. we do have flash memory installed and I don't think its the battery issue cause we changed the battery recently.

similarly, We have another program runs the same way with rx3i and Quickpanel in different part of the plant but power outage or PLC getting turned off doesn't make the PLC loose the program and it works fine.

What could be the issue/.

koliza1 said:

I don't think its the battery issue cause we changed the battery recently.

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I'd recheck the battery, just to be 100% sure is Ok.

It sure sounds like a battery issue. What battery are you using and what is the CPU model? Some CPUs are harder on the batteries than others.
You should also check the settings in hardware configuration. Setting up to always read from flash memory on power-up could also explain your symptoms.

Steve Bailey said:

It sure sounds like a battery issue. What battery are you using and what is the CPU model? Some CPUs are harder on the batteries than others.
You should also check the settings in hardware configuration. Setting up to always read from flash memory on power-up could also explain your symptoms.

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CPU 310 and power supply is IC694PSA040. I am pretty sure we are using high-capacity battery. and I have check the config: on power-up, I have set it as Always RAM.

***another thing I want to mention is that: this program was upgraded about 10 years ago and since then they are having this issue of loosing the program from the PLC on situations like power outage or PLC getting turned off. *****

Seems telling that it happened at the same time they had the program upgraded. To me, that points toward a setting that it is loading something from a memory location on power up.

I'm not familiar enough with Siemens PLCs to point toward the place to check though.

If the battery is loose*, the PLC could lose* its program.