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Unread November 7th, 2019, 06:09 PM   #1
Plastic
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Old Dog Electrician – Functionality Enhancement request to our friends at Rockwell Au

I am an electrician… for a long time. I was the relay guy. In the mid 1980’s, we began using PLC’s. PLC, PLC2.

The programming faceplate decided on at that time was LADDER LOGIC.

This request is to NOT stir debate on what programming language face-plate should be prevalent, enforced, standardized, taught, to the upcoming 2020 engineers of today. (Moving forward)

One of the key benefits of still clinging to our archaic ladder logic is the graphical “GREEN LIGHT” when TRUE logic flow through, and instant graphical visual diagnostic as to what is missing to complete the “rung”.

Albeit, every BOOL instruction is GREEN when true, if mathematical analog compare instructions appeared on the logic line, the user would have to mentally determine if the compare was true or not to de-bug.

My simple request after these some 30-ish years, could our friends at Rockwell Automation make a simple graphical GREEN modification to the graphics when a mathematical compare instruction were true. EQU, NEQ, GEQ, LEQ, LIM, GRT, LES, etc.

Or is Structured Text better for de-bug.. If TAG1 > TAG2 Then ..? Is there instant graphical indication? Or does one need to mentally re-process the mathematical computation for each IF comparison to determine logic continuity or truth?

Thank You

Plastic
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Unread November 7th, 2019, 07:27 PM   #2
Rob...
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Siemens does this already.

I'm fairly sure Rockwell does too, albeit it's been a couple of years now I've touched one and I can't quite remember
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Unread November 8th, 2019, 03:53 AM   #3
parky
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There seems to be a trend to get away from ladder, I think this has been driven by all these standards that have been developed to harmonize the industry (to be honest I think it's jobs for the boys who keep coming up with these). I don't have a real problem with ST etc. As i'm quite fluent in C++, Basic, Pascal etc. but it's sort of been forced on the industry and the IDE's for the new languages have not so far been as good when programming. People like new concepts for example, "A new Iphone got to have it". there is nothing in ST that you cannot do in ladder, after all it compiles into virtually the same code, and in most cases will upload back into ladder (well on some PLC's). ST was supposed to be transportable across platforms, however this is not strictly true as different PLC's, Special function cards & even same manufacturer types do not convert without major changes being required. But again it's down to personal choice, us older stalwarts don't like change very much perhaps our brain cells are struggling to take in more information.
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Unread November 8th, 2019, 10:59 AM   #4
GaryS
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I can see where that would be a plus for you
Why not create an AOI for each compare that would have a bit output that's truewhen the compare is true and use them in you code.
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Unread November 8th, 2019, 12:05 PM   #5
Mispeld
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It would be nice for non-bit instruction to indicate "conductivity" through the rung, but I would not hold my breath for Rockwell to make this enhancement.

A clunky workaround with Logix 5000 would be to put "dummy" OTE instructions after each non-bit input to get a visual cue where a rung's in-condition goes false if the final output is not energized. Though you would not get a visual on instructions after the first false non-bit input. There would of course be a memory and execution impact to this approach as well.
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Unread November 8th, 2019, 12:37 PM   #6
Aabeck
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If I want to monitor something like this I put a line with the compare instruction triggering and output bit.

Then in the usage I XIC that bit instead of another compare.

Plus if the same compare is used more than once an XIC Bit would scan faster than more compares.
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Unread November 8th, 2019, 01:19 PM   #7
thingstodo
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Quote:
Originally Posted by Plastic View Post
I am an electrician… for a long time. I was the relay guy. In the mid 1980’s, we began using PLC’s. PLC, PLC2.
From one 'oldie' to another - congratulations on keeping up throughout your career! I started out replacing relay panels, Black Box (1778) and PLC2 with PLC3 and PLC5 ... so I've got a decade less experience

Quote:
My simple request after these some 30-ish years, could our friends at Rockwell Automation make a simple graphical GREEN modification to the graphics when a mathematical compare instruction were true. EQU, NEQ, GEQ, LEQ, LIM, GRT, LES, etc.
Sorry - I can't help there. The work-arounds described are OK .. like most things .. once you get used to them. But you have to get USED to them.

Quote:
Or is Structured Text better for de-bug.. If TAG1 > TAG2 Then ..? Is there instant graphical indication? Or does one need to mentally re-process the mathematical computation for each IF comparison to determine logic continuity or truth?
Structured text inside the execute blocks of SFC do not change color, or indicate when they are executed .. as far as I can see. I use SFC to control sequences, and use ladder logic to examine the step bits, then drive the outputs. ST appears to be a step backward in troubleshooting, and a step forward in making PLC stuff look like C. My opinion only, of course.

I have been looking for ways to make C, C++, C#, Python, etc etc look more like ladder logic for troubleshooting. I agree that the green .. or any indication .. that shows values, or true/false for conditionals .. would be nice.

Since Python is interpreted, it should be possible ... completely OFF TOPIC for your question though.
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Unread November 8th, 2019, 04:56 PM   #8
NetNathan
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I drew my own...
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File Type: jpg PLC Logic2.jpg (296.5 KB, 36 views)
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Last edited by NetNathan; November 8th, 2019 at 05:08 PM.
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