Favorite Instruction Set?

Regardless of hardware or programming software, what PLC has your favorite instruction set?

I'm in love with Mitsubishi's instruction set. Between things like absolute drum for handling encoders and simple stuff like the rising and falling pulses, it just wins my heart over. GX developer annoys me, but I've enjoyed my limited exposure to programming the FX series simply because of the great instruction set. We're about to retire a bunch of equipment using FX0 controllers and i can't wait to strip them out and have a whole pile of them to use on future projects.

Overall I prefer AB 500 stuff, but it's because of features outside of the instruction set (like RS500's online edits) which is not the direction i'm hoping to take this thread.

OK, I've got to get in quick before all the others descend ...

Best instruction set must have been early '80s vintage Texas Instruments TI 500-series. The one killer instruction was undoubtedly the Event Drum. Sixteen outputs, controlled through 16 sequence steps, with the stepping dependent on time interval, external event (or both) or external jog instruction, all permanently visible and capable of being monitored on a single 80x25 DOS screen. A real work of art by whoever designed it.
Oh, and if that wasn't enough there was the Maskable Event Drum where different switching patterns could be overlayed in the drum at runtime.

And then there were the PID loops - how easy were they? Or what about the Special Function Programs - indexed addressing made so easy - V12 := V200[V20] (i.e. V12 takes the value of what is in V200 plus whatever offset is specified in V20); floating-point calcs programmed the way they would be written x:=y^z * sin(t-1/e)

Life was so easy in those days ...

Ken

Microwin siemens s7 200 plcs..my favourite when I dont need alot of I/O's...every thing you need is there... I just love it! shift registers,PID,etc..

TI-505 Series

Has all the features Ken M mentioned, the later series just built on the great foundation already present. ASCII output is sooooo much easier to do, has a built in print function. On line editing, plus analog alarms! The great thing about this series is that difficult task that would take many lines of code are already built in.

I Just Realized...

Correct me if I am wrong but didnt that GREAT TI 505 PLC just program in ladder?

i like use OMRON PLC.. i think it's simple to make program. i can make from CX-programmer, SYSwin..
and there are have many intruction function can be used

I think if you are going to answer this question, then you should also list all those PLC's you have had enough experience with to be able to say that you have mastered them.

Just listing one favourite in isolation, without giving some idea to what you are comparing it to is pretty meaningless.

i aint a programmer per se but I have spaghettied my way thru:
6200 ipds for the plc5
APS
LogicMaster
VersaPro
MicroWin
Step 7
S5
Whole bunch of different software for the Koyo/Siemens/GE
DirectSoft
Cscape
Does Pico, Easy and that Siemens built (yeah right) Logo count?
Oh yeah, Tisoft and Softshop
I am forgetting something...
CScape (may as well say GE)
Lets see, there is more
Fuji
Cant think of em all
ABB (yuck)
Klockner Moeller (another yuck but its better now

Bunch of HMI's and Scada programs
A few CNC machines.

I may not be good but I can GIT R DONE....
Technically its all the same to me, any language and any plc. I still think the majority of maintenance people ( for that matter many engineers too) will not understand other languages as easily as ladder.

I dont care much for off delay timers because they are rarely used in relay logic and when they are people have problems installing properly etc...

If anyone believes they can teach the majority of maintenance people to understand ladder in a month or so let alone another language is smoking something I want some of. I am not saying they are dumb, its more like "I dont need to know".

I think they are all about the same overall..except for a few that are really aggrevating. I like the S7's but Step 7 has a steep learning curve.

Correct me if I am wrong but didnt that GREAT TI 505 PLC just program in ladder?

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Well...it depends
My experience only goes back to the 560 series, in those you had a 560 processor that only did ladder, but you could, and I've never saw one that didn't, add an additional proccessor that handled loops and Special Function Programs. Without the additional processor it was a TI-560, with the co-proccesor it was a TI565.
The co-processor gave you built in PID loops, easy to configure, analog alarms, easy to configure, AND Special function programming (SFPM). The SFPM was/is structured text programming, the syntax is in my opinion very intuitive, very similar to the old quick basic, but with a lot more PLC oriented functions, such as math, scaling, and print functions.

Later on in the series the seperate functions of the two processors was combined into one. So the later day 545's and 555's come with all the functions in one processor. The newer units handle more loops, something called power math and you can now compile your SFPM's and run them directly in the ladder logic. Where before you had three queue's for SFPM's, normal, priority and cyclic. The ladder would call a SFPM and it would be added to the queue, if the results were time critical you had to program your ladder to wait for the results.

My experience with PLC's has been mostly TI and AB (ML,PLC-5,& SLC)with a little bit of Mitsubishi. For Process control the TI was way ahead of it's time, the new CLX platform appears to just now begin catching up. If I sound biased, it's because I am.

If anyone believes they can teach the majority of maintenance people to understand ladder in a month or so let alone another language is smoking something I want some of. I am not saying they are dumb, its more like "I dont need to know".

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Well, I don't smoke, but I have had good success in teaching PLC programming to engineers and maintenance people. I taught S5 programming at the local college for a few years, and the vast majority picked up on it pretty quickly. Were they experts? No, but they all had the tools to go out there and start troubleshooting, regardless of whether they were elctricians, mechanics, or manufacturing engineers.

monkeyhead said:

Regardless of hardware or programming software, what PLC has your favorite instruction set?

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I reckon the 560 odd instructions (inc. 64 bit Floating Point!)supported by the Omron CS / CJ series has to be a favourite. That's on top of the Structured Text support now offered.
Just my 2 bobsworth
Paulus

You guys are arguing about the best of the deficient.

PhilipW said:

I think if you are going to answer this question, then you should also list all those PLC's you have had enough experience with to be able to say that you have mastered them.

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I haven't mastered any PLC, but I know what instructions a PLC should have. Most don't have the bitwise exclusive or. Some can't do indirect addressing. Some can't pass parameters by value or pointer to a subroutine. Most is not all don't have a add or subtract with carry. Some don't have a 16x16 to 32 bit multiply or a 32 by 16 divide that returns a quotient and remainder. Many PLCs don't support both signed and unsigned integers.

So do any of your PLCs do all the above?

...you should also list all those PLC's you have had enough experience with to be able to say that you have mastered them.

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Absolutely right, Philip. Good point. In terms of real in-depth knowledge I would say I've done TI (all of them) and Siemens S7. So my experience is probably pretty limited. However I have talked with others and exchanged opinions on this kind of thing before, so I think I've gathered some context for my views over the years.

My reason for specifically choosing a time (early 1980s) for the TI instruction set was to avoid the issues associated with a throwaway remark that Paulus made -

That's on top of the Structured Text support now offered.

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Would most people agree that PLCs are gradually becoming commodity items, with fewer unique distinguishing features? The slow but continuing rise of IEC61131-3 languages will eventually render a discussion like this obsolete. You'll either be compliant or you won't be in the game. The genuine differences nowadays are small and simply matters of implementation rather than clear specifications. When I mentioned the TI instruction set, all those years ago it did have one very important characteristic which Siemens have lost sight of as they inherited the range. And it's the thing that software design gurus even nowadays are still preaching, and the item that Ken Moore picked up on, 'ease of use'. Even for seemingly complex tasks, a simple tool was usually available from the instruction set toolbox. With all due respect, Paulus, who on Earth needs 560 instructions?!? Give me 56 well-designed and effective ones any day.

Another biased input? Yep, 'fraid so.

Ken

My first introduction to PLC's was an Omron C20 in 1986. I have training in SLC 500, Limited S7 and C Series 1 and 2.

Step 7 is one powerful program. Working with it opened my eyes.

I had done a couple of SLC 5/03 start ups and one with 4 remote panel that proved to be quite fun and a great learning experience. I was becoming quite adept with the SLC series. That enabled me to pick up the on PLC direct family of brand labels. Those of you that know will understand that one.

Lately, I have done a CJ1 on a couple of ball valve welders with upgrading to VFD's from dc drives. I have upgraded a C200h to a CS1 and will be doing the second of the 2 machines either Friday or next friday.

I have trouble shot a bunch of CQM-1s programmed in syswinn, cx-programmer and something called CC Junior.

I like the SLC 500 APS best of all and it made RS Logix was easy to pick up on.

I like AB manuals for reading and ability to easily follow instructions.

Siemens has tremendous information avilable for the S7 if you want to read the help menu or down load them to a printer.

I have told a couple of Omron tech support types in Schumberg that their programming manuals are not too intuitive. I read the CJ/CS manual and followed the instructions and had problems. I was told to look on the next 2nd or 3rd page and that had to be done first. Always nice to put instructions in order!??? I now read everything before doing anything.

I spend more time fine tuning or trouble shooting PLC's, all brands, than writing LADDER LOGIC.

Thanks to Jay I now have this site and mrplc for resources. I have been looking to expand my PLC programming capabilities and reading about what others have done has been quite helpful

Oh yeah, if you do OMRON you really need to get CX-ONE as it flat out rocks.

I'm asking because programming on the FX series made me realize that instruction set really makes a big difference in the overall experience.

I only have experience with (and wouldn't call myself master of any of them):
AB 500 Series (SLC & Micrologix)
AD 405
Mitsu FX series
Opto22