HMI Recipe Download

So here's the deal, we have a new machine that they were running a speed test on at work today. On the HMI, there are recipes that are "saved." I say "saved" because it appears to me that they are just writing the recipes into an array of DINTS. So, today while they were doing their speed test, they deleted all but two of the recipes and made changes to those two. Long story short, I had to make some changes to the PLC program that required me to download.

Before downloading, I went online with the controller and everything was just fine. I downloaded the program file to the controller and, in the process, completely wiped out their list of recipes and overwrote them with the previous lists of recipes. We use AssetCentre to store all of our .ACD files. Needless to say, the production employees were not thrilled about losing the recipes they had worked all day to develop.

I am wondering why this happened. If I was online with the controller I should have had the current values in the data tables right? So when I downloaded it should have downloaded the recipes they were currently using? I personally think this is not the right way to utilize recipes but the damage is done now! I am just trying to figure out why. We are using a ControlLogix 1756-L7 series controller (I think so anyway, not at the plant right now.) It is in RSLogix5000 so probably version 19 or 20. If anyone has any ideas I would be happy to hear them.

Unless you saved the program while you were online.. Which prompts you to upload all values... The file wasn't updated with the recipes. Thus the downloaded program didn't have the updated array values. You can go online and then offline with a processor and it not save data table values. While online you must save the program and upload values to not lose updated values on next download.

There is also a tool you can install called "Logix5000 Data Preserve Download Tool". It will preserve current data values in the processor during a download.

noxcuses has it exactly right; When Logix 5000 goes online it does a "correlation" with the existing program to be sure they're functionally the same with the same logic and the same tags, but it doesn't upload tag values except as you open routines that use those tags or view them in a Tag Database view or a Watch window.

If it makes you feel better, I've had the same experience dozens of times. It's my habit to do an upload-save-change-name a few times a day.

Thanks guys, I knew it compared the logic and the tags but I guess I was thinking when I went online the data values were the current ones and would stay in there when I download. I think I will be uploading current values before I download from now on!