Data Table Control

[Colin Carpenter 10]

One of the big differences between Mitsubishi and Allen Bradley programming is in the handling of data tables when transferring programmes to or from the CPU. In the Mitsubishi world, if I transfer a new programme to the CPU, then whatever values are currently residing in the data registers, stay there. In other words, the programme only transfers the programme and nothing else. Using RS Logix 500, if I transfer a programme to or from an SLC5/05, then the values in the data tables are transferred along with the programme. This is fine when transferring FROM the CPU, but can cause a problem when transferring TO the CPU in the event of replacing the programme with an older back up version. Question is: Can I elect not to transfer data table values? I have a feeling this is a pretty simple question ...... but I don't currently know the answer.

[jstolaruk 9]

No, you can't, and I put in a request for that very option over on the Rockwell site and didn't get a reply. Two different ways around this is to: 1. make your changes online into the machine whose data table you want to preserve. 2. Open two RSLoigx windows, one online and one offline and copy/paste the data tables you want. You can ctrl-c ctrl-v in the project tree. Edited 16 Feb 2006 by jstolaruk

[Colin Carpenter 10]

Thanks for that. I thought it was just me that was missing some simple option in the software. It does cause problems. The other day, after an online editing problem, we had to reload a backup copy of the software to ensure that there were no other bugs that had happened without our knowledge. Problem was that the plant had "moved on" in those hours, and the back up software re-wrote data words, so that tanks that had been cleaned, were now showing product names etc., etc. The "snapshot" of the backup is not necessarily the true status of the plant now ..... spend another few hours changing bits and register values to enable the plant to carry on doing what it was doing, so that all the interlocks are satisfied. Would have thought it would be a pretty easy thing for Rockwell to sort out?

[lynchmob2000 0]

Depends on the controller. FYI, from the RSLogix500 help file. Data Table File Protection is available with any of the SLC 500 processors. However, the form of protection can only be changed during offline programming. MicroLogix 1000 There is no data file protection on these controllers. MicroLogix 1200 and 1500 You may protect selected data table files from being overwritten on a download or when being loaded from a memory module. Apply this protection when you create the data file from the Create Data File dialog. Fixed and SLC 5/01 processors Output files are always statically protected and all other files are unprotected. SLC 5/02 processors Before you save your program you can statically protect output files, all files, or no files. Apply protection from the Controller Properties/Compiler Options dialog. SLC 5/03, 5/04 and 5/05 as well as MicroLogix1200 and 1500 Series Bprocessors only You can choose between static or constant protection for data table files on a per file basis. Apply this protection when you create the data file from the Create Data File dialog. Memory module overwrite protection is also available, see MicroLogix 1200 and 1500 above for details. Terms Constant protection protects values in the data table file from all changes via communication ports or your ladder program. Static protection guards data table values from being altered by communication channels. Changes are only allowed by the ladder program during program execution. Hope this helps.

[Colin Carpenter 10]

Have looked at this topic again, due to being closer to working on the PLCs, and thought that the protection mode might be the answer to the problem. Unfortunately, further investigation the AB web site revealed the following: >>> Check Constant if you want values in the data table file protected from all changes via communication ports or your ladder program. Choosing this option protects the datafile from being over written by a MSG write instruction coming in via the processor communication port. Also, constant protection protects the file from being over written by an instruction in the ladder such as a MOV instruction. NOTE:This does not protect files from being over-written during Download operation nor does it protect the file from being over written by a Load from EEPROM operation! Check Static to protect data table values from being altered by communication channels. (Again, this does not protect from Download or Load from EEPROM operations.) << Seems like nothing protects the data tables when downloading Surely there MUST be a way of doing this? ...... it causes so many problems.

[Firetubes 1]

The PLC5's will let you do partial downloads of program files and data tables. This is not available with the SLC500 and I don't know why they didn't implement it on the ControlLogix. It's a good feature to have for problems you're experiencing. Your best bet is to do what jstolaruk's item 2 right before a download.

[Colin Carpenter 10]

I've kinda tried that .... but not actually in a "live" mode. I opened two RSLogix windows and started a new project in one and an existing project in another, both projects having different names. I then tried to copy data tables from one project to the next, but found that it wouldn't work. Copying and pasting ladder files works well, but not data tables. Obviously these are different file names and RS Logix was not "online", so maybe it would work in that instance ....... still a bit of a "spooky" thing to have to do, though.

[swimmy67 9]

Colin, During my years programing the SLC 500 or even the MicroLogix PLC, I have got into the habit of uploading and saving the existing program residing in the PLC before I do any edits. I too have found out the hard way that the data could be different from a backup file that was used for the first download. I have applied this practice on all of the PLC's that I work on. If I go to a customers location to edit the program, I first upload and save the existing program even though I have the original copy of the program. I want the latest and greatest program to fall back on. I hope this helps. swimmy67

[TimWilborne 108]

I will make notes of the rungs I am adding/editing. Then when I am ready to download, I upload the program to make sure I have the latest information, then copy and paste the edited rungs into the uploaded program.

[jstolaruk 9]

I spent many years on PLC5s before ControlLogix and SLCs took hold (did one PLC5 project last year and have one later this year) and am not aware of this feature. Are you sure and if so, can you point me to that feature? Thanks, Jeff Edited 10 Mar 2006 by jstolaruk

[lynchmob2000 0]

Just to be clear..... The Micrologix 1200 / 1500 files can be protected against download and the SLC's cannot be protected against download ? I too always upload first if possible, but I'd like to know for sure.

[Colin Carpenter 10]

Me too ... went to site the other day, uploaded and saved the programme, took a few hours to work out the mods, did them on line, messed up somehow (still not exactly sure how), had to hurriedly download the program that I had uploaded a few hours earlier (and saved for security) .... then had to sit there for hours manually finding and updating the important data table values (tank status etc) that had regressed to a point in time several hours earlier, even though the world and the plant had moved on during that time. Maybe copy and paste of individual rungs when in online mode is the best way (short of swapping it for a M*ts**is*i). < Exits, Stage Left, Ducking to avoid Missiles>

[TimWilborne 108]

lynchmob2000 is correct. You can keep data files from being overwritten on a download with the Micrologix 1100,1200, and 1500. But I would still rather upload before editing just to make sure that no one else has made program changes. Edited 10 Mar 2006 by TWControls

[Snerkel 0]

Open your new project, open the existing project online. Open the data file you want to reflect in your new software, eg N7 hold down shift key and select all the values using the arrow keys. Copy them then go to the new prog open N7 and paste the values.... job done.

[TimWilborne 108]

Thanks, didn't know you could do that. I wish they would make it so you could do that in RsLogix 5000

[jstolaruk 9]

I just copied and pasted subroutines between two sessions of RSL5K. I'm running v15.01. I don't know if older versions are not supported. Still would like to know about RSL5 selective download capability. Firetubes? EDIT: never mind, found it! Just never had a reason to use it. Edited 10 Mar 2006 by jstolaruk

[TimWilborne 108]

Snerkel copied the data file values from one program to the other. Subroutines work fine in RsLogix 5000 but does anyone know a way to copy tag values between two programs?

[Firetubes 1]

Another way is to save your application in the *.SLC (text library files) format and then cut and paste the data table (or program files/rungs) sections from one file to the other. You can even select a group of rungs and save it to a *.SLC file (partial save) then open it and import into another *.rss file. This method will export/import all rungs you highlighted and any datatable values that are used in those rungs. This is good if you made changes in only 1 program file and not all over the place. The import will add the rungs where your cursor is at so make sure you deleted the old rungs first and pointed to the right place. I haven't tried it on the Controllogix *.L5K file type but you should be able to do something similiar, especially the tags.

[Ken Roach 194]

ControlLogix has a Tag Upload/Download tool that I've used to overcome this functionality. The idea is that you'll do an upload of all your tag data into the utility just before you perform a program download, then do the program download (which overwrites all the tag values) and perform a mass Tag download to restore the operational data. The tool is a separately-installed utility (included on the RSLogix 5000 CD, but not installed automatically) that requires an RSLinx installation with OPC capability. I have used this on systems with a lot of internal trending and level recording and it works really well. You lose only a few tens of seconds of data during the download.

[TimWilborne 108]

So thats what that utility was meant for By this do you mean a RsLinx other than Lite?

[hipoint2 0]

I agree with swimmy, I have been burned to many times by letting people tell me that they have all the backups and that they are the most recent. Bottom line go online and get a recent copy before you do anything.

[Colin Carpenter 10]

Hmmm .... there is a tag upload / download tool on the AB site which claims to work on all Allen Bradley PLCs .... SLC, Control Logix etc., etc. Link is: www.software.rockwell.com/support/download/detail.cfm?ID=2788 Not sure whether it needs a specific version of RS Linx though as I don't have an easily accesible SLC to play with at the moment. Interesting ...... Edited 21 Mar 2006 by Colin Carpenter

[Wordman 0]

Can you create new data files using partial download?

[Firetubes 1]

Yes you can d/l new data tables. You can d/l new program files too. I think there are some caveats but can't remember all...like download the data table first if they are new and used in the ladder file that you are going to partially d/l.