General RSS file attribute questions

Hello all,

I am currently working on a project involving SLC 5/05's. There is two treating vessels, #1 and #2. #2 was recently (2008) upgraded from pneumatic systems to electronic (temperature, pressure, vacuum, etc). Now we are upgrading #1 to the same electronic controls. #1 is a little fancier with a larger PanelView Plus 1250, and we eliminated all the toggle switches and indicator lights by moving them into the HMI. To get a starting point for this upgrade, we used the existing code on the panelview 650, scaled the display size, and added a few more pages. Now, on the PLC, we weren't given a copy of the final file that went into the SLC 5/05 back in 2008, but we had some (what we thought were) previous revisions of the file that the boss declared "good enough to get started" with...

I believe we are now faced with a situation where we have 3 versions of a file: the "original" file we started the #1 upgrade with from 2008, the modified version of the aforementioned file, and now I may have found the "final" version of the file that went into the 2008 upgrade.

When performing an UPLOAD from the PLC of the upgraded #2 system to our laptop, RSS Logix 500 said it could not find the matching file to use. We browsed through the collection of folders until it said we had a match. It then went online, and all seemed ok. I checked with the boss, and he said to use this file if it matches. Well, I have no way to verify that it does match what's supposed to be in the machine. I was not involved at the time of the upgrade in 2008.

My questions are regarding the actual RSS files, RS Logix 500, and upload/download operations.

1. Does RS Logix perform any sort of CRC or bit by bit comparisons to verify that file contents match exactly between what is stored on the PLC and what is on a local disk? What criteria is used to determine an actual "match" between the onboard logic and a local file? Thus far I believe it to consist of matching the processor name only...

2. Is there any way to "merge" two files? (other than having a copy of both open and moving everything different in a comparison)

3. What sort of information inside the logic ladder will NOT be copied from one file to another? We have so far found various strange "holes" in information such as PID's with no tuning parameters, missing comments and descriptions (that are in original file).

Any further clarification needed, please ask! I don't have access to the files (they are at work) but can relay or gather information as needed.

If you performed the action in the third paragraph and saved that what you have is the logic, configuration and data tables from the PLC. This was merged with names, descriptions and rung comments as found in the RSS file on the disk. The best action would have been to save the merged result to another file name. The 'doesn't match' comes from a mismatch in the file checksum compared to the PLC checksum but the CPU Name probably matched (an important reason to set the CPU name uniquely). An incredibly small difference can cause this. As this was code running, I presume, on a system the logic, configuration and data tables should be good. Check the documentation for a general match with any printed forms of the program.

When I have two program which I have to merge I create separate working copies of the two programs. I check how I/O, program and data files may overlap and plan for the new structure. I generally try to keep the larger program intact. I move the I/O, and tables on the smaller.

Then I create the final program. It is a copy of the larger program in which I create the empty program and data files for the smaller program. I use copy/paste on the ladder rungs and the data tables (yes you can move the contents of data tables this way between totally different programs.) Finally there is any linking code, possibly new JSR's in ladder 2 at least. There's always something I miss so I set aside significant time for testing.

Thank you for the input so far!

I wish to make sure I understand this, so far. If we used the file as described in paragraph #2: all logic should be exactly as what was in the PLC, comments and descriptions may or may not be in there depending on what was stored on the local disk, and data tables and PID tuning parameters would be whatever was on the running system. The lack of PID tuning parameters has me feeling there may be something else missing.

I will try to bring my work home with me tomorrow, and see if I can sort out what files are supposed to be. If I upload a copy of system #1 and #2 working logic files, can I still see the controller checksum properties offline, or is this only shown when online with the working logic?

I suspect this is another of those "here's the machine, sorry there's no documentation" scenario's ...

See picture for program check (yes offline)

just a follow up for any who are interested...

I did check the files (both online and off) checksum, and the two files we have for the #2 system match checksum, but the contents of the file differ when I open them offline (descriptions, comments, and even some bits are different). But if I am online, and go offline with the file already open, it's all there. Strange behaviour.

I ended up using your method, Bernie, for managing the two files. I had to use the compare tool, and examine each file line by line, and copy the changes to a new file (started the new file from the re-worked #1 system file). All in all, I learned more in those 6 hours than the last few days, probably!

All seems to be working now, according to the operators at least.

Thanks again for all your inputs...