Nested rungs PLC5

How does the PLC interpret nested rungs?

Does it read them from left to right (branch closest to left rail first) or top to bottom?

This is for a PLC5 instruction.

Look at the text representation of a rung.

If you don't know how to see the mnemonic representation of a rung, double click near the rung number on the left side. This opens the mnemonic editor. What you see is what you get.

Missing the point

I don't follow your reply.

I have a rung with three nested branches; outer branch grt'
inner branch les and innermost branch cpt.

-----+--+--------cpt--------+--+-----

|--les------mov-----|

|-----grt------mov--------|


Does the PLC process the grt then the les then the cpt or the oppisite way (cpt les grt)?

No matter how I try I cannot get the ascii char's to exhibit how I am typing them in to try to convey to you the nested branches.
I hope it makes sense to you as it appears

Thanks Alaric

As I was typing I guess you were also.

THANKS! I did not know how to show the mnemonic string.

That answers my question plus a couple unasked ones I also had.

Thanks again

When I read my text descriptions of nested branches on one rung it looks to me like it reads one branch at a time, left to right.

Correct me if I'm wrong: On parallel branches, would it read through all branches top to bottom first, THEN left to right?

Scottsull,

To get ASCII characters to display as they would in ladder logic, you need to be using a fixed-width font that treats all characters including spaces as taking the same amount of horizontal space.

On this forum, you can force the system to use a fixed width font by using the {ladder} {/ladder} tags. You can also use {code} {/code}. Use square brackets instead of the curly brackets to designate tags. Put your ladder logic between the tags.

Here is ladder logic without the use of tags.

--] [------------( )-
|
--] [----+

Here is the same logic using the tags (even though you can't see them).

--] [----+-------( )-

         |

--] [----+

Als, don't preview your posts with ladder tags. For some reason, spaces get stripped when you preview or edit.

Greetings ascot01 ...



here’s the secret handshake:



do the “text representation” that’s already been described ... then read through that text going from left-to-right but mentally LEAVE OUT the BST, NXB, and BND instructions ... those just mean Branch Start, Next Branch, and Branch End ... important: those don’t affect the TRUE/FALSE state of the rest of the rung ...



once you’ve left out all of the “branching” clutter, the rest of the code should make sense - and (most important) it will be IN THE EXACT ORDER that the PLC processor will execute it ...



hope that helps ... if not, please post an exact example and we’ll work through it with you ...



NOTE TO OTHER POSTERS: this is basically an "old thread" ...

NOTE TO OTHER POSTERS: this is basically an "old thread" ...

Click to expand...

Oops,

Thanks for pointing that out Ron.