Decrypting some one else's code?

Hello all!
I have an old micro 300 that I am working on replacing to a c400 panelview component . The issue I am having is decrypting the panelbuilder 32/ PLC code.
The micro 300 only uses 3 three tags N7:2, N7:10, and N7:30.
It has 92 display screens some screens have numerical settings along with the screen it is on but it doesn't show a seperate tag for the value it just gives me the screen number and integer associated N7:2.
(Example) Pan variety ## I right click select the number tag select properties it just shows Data 1 display (NODE) SLC. Tag address N7:2. I would think there would be more or they would of used a counter in the tag address for that screen. The N7:2 is used through out this project and same for the N7:10 ,and N7:30. When I search N7:2 on PLC program it actually isn't being used in the program it cross-references to other files.

But that is my issue any help will be appreciated.

They are probably using indirect addressing (or a whole lotta MOVes) in conjunction with Control and Status tags.

Look in the Panelbuilder file at Application Settings Status Tags and Control Tags.

The original programmer is probably deciding what N7:2 means based on the display number that is active. If you are allowed by your company policy, zip the pb32 and RSS files and attach to a post and we can probably nail this down for you.

Thanks for the response.
After I posted the first time I went back searched N7:2 and it came up in the program so I must of missed typed it when I did the search.
But I still need to figure out how it calls for each screen when needed.

I added the zip files to this post.

The HMI looks at N7:30 for the screen number from the PLC.

N7:10 is copied into N7:30 in LAD2 Rung 1 when B11:1/0 is on.
N7:10 is what the PLC program uses for the next commanded page number.

There are a lot of instructions through out the PLC program that load a number to N7:10 to change the page.

B11:1/0 is set by the sequencer logic in LAD18 Rung 11.
I've never used sequencer commands, so can't really explain them very well.

Thanks Picklemon for helping me understand a little more on how it works. It makes sense to me. I just have to figure out the SQO instruction.
But thanks again.

Looking at SQO instruction it requires an on/off trigger but since that rung is true all of the time how does it sequence?

The "SQO" instruction increments the position value on a false to true transition of the rung. In your case the position value is being controlled by lad 18 rung 008. A "MOV" instruction moves N7:11 to R6:6.POS. Do a search for what controls the value in N7:11.
The "SQO" instruction will execute every scan the rung is true. If the position value remains the same it will keep writing to that position every scan.

The program is also unlatching the enable bit in the control element after the SQO is executed. See rungs 13-15 of LAD18. I think this would allow the command to execute every scan as a false to true condition. This pattern is used a lot in this program.

thiefgold0913 said:

Hello all!
I have an old micro 300 that I am working on replacing to a c400 panelview component ...

Click to expand...

Did you already buy the C400? You know that Panel is not very fast, right? Specially with that amount of screens.
I've used the C400 a lot, and would really recommend you to use the (sucessor) PanelView 800 instead, cause its a lot faster.
The C400 has a very long boot up time, and for development and debugging thats very annoying.

(To Crawler009)I already had a spare C400 at work since we have other equipment at work that uses it. But I like your suggestion. I know the c400 is discontinued or the part number changed from I was told when they reordered.

I am going look into the program more today from the suggested help listed. Thanks again for the help.