"Translate" Simens STL?

It's been a long time since I have really been deeply involved in an S5 or S7 program. But from what I remember, looking at the network as it was originally shown, the RLO is never explicitly set/reset anywhere along the network. It's active status just keeps working its way through the network and is evaluated as required along the way. About right?

If so, the FBD format would tend to show that better than other formats.

Keith
 
The FBD does not display in LAD because it breaks the LAD rules in having a second "rung" doing the reset of M2201.0


This can be overcome by adding an inline coil and a second network and then you can see the code in LAD format.

sst2.jpg
 
I guess my question is less about display and more about functionality. It specifically has to do with the post made by sigmadelta. His post would seem to indicate that you can break the network logically at the "output" instructions, paste the rungs as separate networks and it would work correctly. This is correct if the RLO is explicitly set at the occurrence of every "output" instruction. However, if the state of the RLO remains in the state it was as a cumulative result of the previous logic, then just breaking apart the network doesn't produce the same result.

Keith
 
Yeh, possibly, I know there were versions that were not Siemens, especially S5 One company I think in Birmingham supplied S5 for windows, It was actually better than the Siemens Step 5 which was a CPM program running in an emulator. so was actually running in CPM.
Maybe the code here was used to confuse people, came across a program in S5 where a timer was passed to a function, this was decimal values such as 257, This confused me a bit as there was only timers up to 255, but realised that when a timer was indirectly called, it only loaded the lower byte for timers so 257 actually pointed to timer 1.

DO = Timer process the value passed to function (257) 16 bit operation
L T0 Load the timer pointed to i.e. 257 that = 1 only 8 bit operation


Was this software called Quadriga?
 
I guess my question is less about display and more about functionality. It specifically has to do with the post made by sigmadelta. His post would seem to indicate that you can break the network logically at the "output" instructions, paste the rungs as separate networks and it would work correctly.


This is correct. I use this type of method to re-create 'broken' ladder by joining together the separate networks again afterwards.
 
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Create a new FC in FBD. Change the view to STL. Copy your network 27 into the new FC. Change the view to FBD where it will display correctly (see below). Change view to FBD in the original block and delete your problem network 27, copy/paste the network from the newly created FC back to where network 27 was.


Thanks, came back to tell you guys that it worked, putting it into a new FC as FBD. That helps a lot, and thanks for all the answers.

It never crossed my mind. Because as I said, converting from STL to something else has almost never worked for me.

Maybe i'll use this to try to make more sense of STL.
 
Just for clarity for those who take things too literary, I would not publish on any site. I will only help people who can prove to me there is a valid reason, even then I will not divulge, only do it for them. But now I'm retired would require them to come to me with all relevant information. Regarding the software I think it may have been Quadriga but not sure. They also made Ram & Eprom cards at a fraction of the cost, after all a couple of 2708 Ram chips on a bit of board at a cost of ÂŁ800 was a bit steep.
 
// If you want to just get to the "meat" you can scroll pat the intro. :)

// TLDR = we've all been there mate
I know that I'm a little late to this conversation but after reading thru all of the previous posts about how to convert STL into LDR so you can more easily understand it, I feel like a few helpful pointers will avoid all this in the future. Early on (back in 1998-89) when I started working with the S7 plc the group I worked with wrote everything in ladder so like most of us I could easily figure out that when the NO contact was active the green line (RLO) continued on to the next element to the right of it. After awhile I start feeling confident that I know PLC programming and then I encounter a program written by a different group in our company that used STL and now I'm a little confused. Luckily in SIMANTIC Manager the help function (F1) is very informative and I was able to figure out the program to finish commissioning the new equipment. And you're wondering why I need to tell this story to make a point - I don't but I feel it does convey that we all started out not knowing much about Statement List. Another thing that helped me was understanding logic gates. When I was reading the help files on all those A's, AN's, O's, ON's, "(", ")" and "=" I realized that the were basically describing inputs, outputs and grouping of AND and OR logic gates.

// OK w/FBD?
The OP mostly shows bit logic in statement list format. If you understand FBD (or logic gates) just imagine each A represents an input to an AND logic gate. The output of the logic gate (or group of gates) is the "=". Similarly O is input to an OR gate and ON or AN is negated (or inverted) input to the gate.


******** Don't know FBD but like ladders?
If you are not that familiar with FBD and you want to think in ladder until you get the hang of it.

AND gates are like having contacts on series. You can re-write STL to ladder by writing horizontally across left to right each A becomes a NO contact and each AN becomes a NC contact then at the farthest right the "=" is drawn as a coil. Or you can go the other way, you can re-write a ladder to STL by writing vertically down the list so each NO contact is an A and each NC contact is an AN then at the end of the list put an EQUALS sign to represent the coil.

OR gates are ladder contacts in parallel but the same idea.


// If this helps 1 person, this wasn't a complete waste of time.
 

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