no more FB, ST, SCL, or CFC... Ladder only

[#ANotJstMenEngr]

Well i have found myself in a purely ladder programming environment at new engineering company. I have done troubleshooting and of course it was the first plc interface I learned....oh that was long ago and so many updates and legacy put to rest. Here's my problem: need to store several analog values (Temperatures, gallons, weights, speeds and positions in degrees) then handle calculations, comparisons, and assignments for use in both HMI and PLC. Normally would create FBs and call it when needed to pass values into DBs. I'm sure that is exactly what is happening as well in ladder but darn if i can get easier way that doesn't require 30 to 40 rungs of multiple elements on each rung. Any thoughts on smaller subroutines? I will understand if 30 to 40 (or more) rungs is SOP.

Thanks in advance

 

[Steve Bailey]

Capabilities vary widely depending on which PLC platform you're using.

 

[jparale]

Different plc has different way of programming but doing the same thing. and as steve said capabilities widely varies depending on the flatform...

 

[#ANotJstMenEngr]

Using various 1700 series Allen Bradley RSLogix 5000: version 13 to 21:

 

[Keystone]

Using various 1700 series Allen Bradley RSLogix 5000: version 13 to 21:

If they are repetitive tasks with different variables you could make some AOIs or UDT to accomplish some routine task and simplify your programming.
I have made several that I routinely use, really speeds things us.

 

[LadderLogic]

Normally would create FBs and call it when needed to pass values into DBs.

That is what a PC programmer would normally do. Now you have to learn to think like an electrician rather than a programmer

 

[DwSoFt]

That is what a PC programmer would normally do. Now you have to learn to think like an electrician rather than a programmer

haha so true. you hit this one on the head!

i think its silly to say no function blocks what so ever... that is what a PID loop is for exam0ple, as well as the scaling function (AB of course). i think this new firm just wants something the electricians can read easier when troubleshooting

 

[#ANotJstMenEngr]

If they are repetitive tasks with different variables you could make some AOIs or UDT to accomplish some routine task and simplify your programming.
I have made several that I routinely use, really speeds things us.

I will dig into AOIs and UDT usage in AB.....much thanks

 

[#ANotJstMenEngr]

haha so true. you hit this one on the head!

i think its silly to say no function blocks what so ever... that is what a PID loop is for exam0ple, as well as the scaling function (AB of course). i think this new firm just wants something the electricians can read easier when troubleshooting

I will be required to use PID loops and scaling with AB (not yet the "Fan"). Working with the tools before me, just want to utilize every option to fullest.

Thank you for the insight

 

[Manglemender]

Surely you should be writing your own PID loops in ladder. And while your at it, sell your car and buy a horse.

Nick

 

[#ANotJstMenEngr]

Surely you should be writing your own PID loops in ladder. And while your at it, sell your car and buy a horse.

Nick

Well as mention this is my return to Ladder not just to troubleshoot but to create from scratch. Just trying to get to the optimum usage from my efforts.

 

[Manglemender]

I meant no offence so I apologise if it came across that way.

It amuses me when companies dictate things like "only use ladder". The other customer comment that, as an integrator, used to fill me with dread was "we've developed our own library of blocks for you to use"; they were mostly rubbish.

The right tools for the right job. You could sell your car an buy a horse but you'd be a bit mad. You could write your own PID in Ladder but you'd be a bit mad.

Nick

 

[kellian]

Currently working the other way. Going from AB to Siemens.
my take is AOI = FB, DB = UDT.

 

[JesperMP]

Of course Ladder is the best choice for some tasks. Especially binary logic code (with a few compares thrown in) is perfect for Ladder. But for some other tasks Ladder is not the best choice.

Some tasks are very easy to accomplish in Structured Text, and when done properly the code is immediately comprehensible.
The same code made in Ladder will be bloated and not nearly as easy to comprehend.

 

[#ANotJstMenEngr]

I meant no offence so I apologise if it came across that way.

It amuses me when companies dictate things like "only use ladder". The other customer comment that, as an integrator, used to fill me with dread was "we've developed our own library of blocks for you to use"; they were mostly rubbish.

The right tools for the right job. You could sell your car an buy a horse but you'd be a bit mad. You could write your own PID in Ladder but you'd be a bit mad.

Nick

No offense taken, I am somewhat out of my comfort zone so I wanted to get others opinions. I thank all who took the time to give their insight.