Let's design the Ideal PLC!

[Terry Woods]

Hey! It's the Internet! All of us can voice our opinions on what makes a reasonable PLC! Think in terms of... "What if...".

With that in mind, how would YOU develop the "Ideal PLC" to be programmed and configured?

That is... If YOU were developing the design-spec for a new PLC, what would YOUR spec include?

I will add (impose?) one consideration... "WE", the programmers, i.e., the USERS, are HUMAN! And as such, "WE", the HUMAN-USERS, tend to think in terms of Base-10!

So... how would YOU spec your new PLC?

Think very carefully about this before "Shootin' from the hip!"

What is the most "Natural" and "Intuitive" way to think when it comes to Process Control? And, how can that be applied to PLCs?

The basic idea here is... what does it take to make the PLC predisposed to think more like "WE" do?

As a side question... Are there cases where "machine-think" might be better than "human-think"?

 

[darrenj]

First suggestion..Tag based programming..I love it!! AB and rslogix 5000 did that right..

Lots of other ideas..just cant get them from the head to the keyboard

 

[CroCop]

Tag based
Text available
For loops, while loops, etc.
Built in function blocks
User defined function blocks
Motion control seamlessly
Ethernet programming is a must (preferrably with a gig connection)
Process control that is flow chart based (I like flow chart sometimes)
I'll add to this.

 

[Doug_Adam]

1, Standard PC connection type. No special adaptors. In the past, this would have been a straight serial connection such as the Modicon Modbus connection. Now it would either be a USB connection or Ethernet.

2, Support for standard bus types built in, or a card available. I am talking about Profibus, Device net and others.

 

[jstolaruk]

Tag based, optional finite state machine (FSM) bubble diagram programming.

 

[CroCop]

Auto configure the drivers (like a USB 2.0 plug in)

 

[monkeyhead]

Hey! It's the Internet! All of us can voice our opinions on what makes a reasonable PLC! Think in terms of... "What if...".

{...snip...}

Think very carefully about this before "Shootin' from the hip!"

You said a bunch of people on the internet should post their feelings without shooting from the hip? Satan must have just ordered a winter coat.

Anyway, features that make a reasonable PLC? Good instruction set, good programming interface, online debug/edit abilities, and ability to communicate over a plethora of com protocols.

Okay... so that makes a good platform. A reasonable platform has all the tools that are needed to get the job done without re-inventing the wheel.

 

[MarkTTU]

One big block of memory that can be defined as I need it for any particular job. IE, if I'm writing a program that needs 10,000 timers, but only 100 internal bits, then let me create 10,000 timers and 100 internal bits. If another project needs 100,000 internal bits, but only 10 timers then let me configure it that way.

 

[Peter Nachtwey]

Why bother?

No one will agree on what the perfect controller is.
You can't implement the features anyway. So many have visited this site and asked about how to implement a PLC or have told us they are going to implement a PLC. Not one has said they have finally done it.

Now why don't we narrow the topic a bit like. How does one implement tag names? How does one implement on-line programming? What can be done to fix AB problem where the data get downloaded with the code? Should the ladder, ST, FBD or IL compile down to machine code or an interpreted P-code?

 

[CroCop]

All IO cards with built in high speed counters.
Higher resolution/speed stuff like National Insturments (data aq. and all)

 

[CroCop]

All IO capable of digital in/out, analog in/out

 

[goxx]

relay inputs/outputs option
special relays, ie 1 second on, 1 second off timer

 

[HLeap]

I vote for one where Documentation as well as the Ladder Logic is stored in the PLC memory.

 

[rdrast]

Me?
I want to see the ability to handle Datablocks as well as Siemens S7 (online modifications possible) but still have the unlimited nested-inclusions as Logix 5k allows. I'd also like to see Logix 5k's 'comment fallthrough' on datablocks to go through every level, and not just the initial and terminal.

I also want ultra high speed numerical calculations, in formats from everything from integer to double precision floating point.

For programming, and editing, I'd like to see something that supports languages such as SCP (Siemens), but with a more flexible approach. Like an AB ladder 'Box' construct that you can open up and type an SCP function in.

It must have Ethernet, but should also be able have the ability to talk to any industrial network out there, in both master and slave modes.

Just a few thoughts, just got called to fix a problem.

 

[Goody]

There should be memory that is just like PC memory. Where you can store just what you want in there. Word doc's - pdf doc's CAD drawings etc. The whole program with comments - labels and code descriptions should be in there.
Just imagine that - you come to a machine you have never seen before and the tech drawings and info are all in there inside the PLC.
With cheap memory today, it should be standard.