future of exisiting PLCs against the Soft PLCS

[Doug_Adam]

My first look at a soft PLC many years ago, I would have said "Yes".
About that time (1998), a large number of PLC manufacturers were working on a soft PLC. (Schneider, Siemens and Rockwell come to mind)

About that time, the larger, higher end PLCs seemed to suddenly drop in price, an a lot of these projects seemed to die off soon after.

So, where would one fit?

Firstly, a soft PLC will only really replace the PLC CPU. Your IO will look no different from what it does now. Modern PCs usually only have a few card slots, so the old days of an XT with 8 slots and 200 IO is out. So in light of that, my opinions:

Small, low end relay replacement? - Brick PLCs win easily.

Mid size? - I would still go for a PLC

High end, need nifty maths functions, 100% reliability not critical, - Soft PLC.

High end, standard functions, take your pick (I would still go for a PLC due to reliability)

Time on your hands, old PC available, need a hobby, - Soft PLC.
(Confession: Old PC available, Linix CD ready, link to Mat PLC in favorites, no time, Toddler uses prospective soft PLC to climb up to book shelf and throw top shelf books onto floor, wife making comments about leaving useless rubbish lying around)

Student, need a good final year project - go finish the MAT PLC.

My opinions only,

Doug

 

[akreel]

Another big problem is that every bit weenie in the IT department will now think they can do automation - its just another PC app, isn't it?

IT'S WORSE THAN THAT!!!

Your dim-wit IT department is going to assume they know better than you. So, if you request Windows2000 Server on the machines running you SoftPLC, your IT department is going to give you Windows2003 Server. Trust me! It will happen! We've had this discussion before, regarding laptops for programming PLCs. In the end, the creative solution (to baffle the IT geeks) was to buy a laptop from the PLC vendor and have it billed as a "PLC programmer."

At least with a PLC, management and purchasing don't have a clue what they're looking at. They have to trust your judgement.

AK

 

[BobB]

If IT is a problem, put all Ethernet on the closed network 10 without telling them. They hate that. Also password protect everything. They hate that even more, believe me. I do it regularly, after discussion with my client's engineers. After 1 year and a day I do not really care what they do and give them the passwords. Defects liability is then over. But, just in case someone wants to sue me, I make sure I have a copy of the software as I left it. I also make sure I save it on the appropriate day so that at least the date stamp may bear some scrutiny, if challenged.

I was invited to address a Device Net conference here in Sydney some time ago. Had a couple of largish Device Net jobs in progress. My invitation was from Omron, but that is irrelevant.

The idea of the conference was to promote Device Net and most vendors were present and doing presentations.

Cutler Hammer have soft PLC. They used the occassion to heavily promote soft PLC. Not in the spirit of the conference and the attendees let them know it.

Thye majority of customer attendees absolutely panned Soft PLC due to the fact that it runs on a computer. They all considered computers and Windows unreliable for any critical or production applications.

One guy apparently had a big argument with his IT department and his engineer. IT had been in the engineer's ear obviously. He finally settled the argument at a production meeting when he insisted that if IT pushed the Soft PLC issue, they issued him with a signed document guaranteeing that the computer and software would be at least as reliable as the PLC system and that they would accept any blame for loss of production due to a PC or software failure.

I spoke to him just recently and he tells me that there has been a deadly silence from IT ever since.

 

[CaseyK]

Let's see, a PLC runs equipment.

Typically doesn't play games, videos, or songs. Normally doesn't have to have it's "windows" cleaned. Usually doesn't connect to the internet, may belch, generally doesn't die, and isn't doomed by the "blue screen". And can't play solitare, unles there is one heck of a good programmer put there.

So why use a computer??? So when you are board you can slip in Anne Murray or Led Zeplin. Catch up on the Stock market or recent PLCS.net posts, get in a quick hand of solitare, spend an hou playing bejeweled...

Wait, if you have all that time playing on the computer, who is out there trying to make the stinkin PC System run after it crashed.

PC's are for programming and playing games. Period

enough rant.......casey

(PS - I HATE Steeplechase!)

 

[elevmike]

Let's see, a PLC runs equipment.

And can't play solitare, unles there is one heck of a good programmer put there.

Casey If only the PLCs had a random number function. then we could make it play games!! I've tried, and tried and tried but no luck without an RND instruction. banghead

 

[rdrast]

Casey If only the PLCs had a random number function. then we could make it play games!! I've tried, and tried and tried but no luck without an RND instruction. banghead

<smile> I have a generic canned random generator routine I use a lot. It's 16 bit, but can be expanded if you like.

As soon as you get the card handling, score-keeping, and display handling down, I'll send ya a copy !

 

[elevmike]

Random Number Generator.

rdrast,

I'd really like to see that RND code. I want to apply it on an AD DL06. First game is roulette. (seems much easer code then cards etc..) RND generator picks number between and including 1-38, then just add or subtract bets.

Thanks, Mike.

 

[CaseyK]

With enough registers, timers, math functions, etc, it could be done.

For the time to program it, at $25/hr, then HEY DUDE, BUY A DELL!

With Walmart coming out with a $499 laptop........

icky - ask the boss about getting a solitare module for the DL06!

Given enough time, the outstanding resources on this site (hey, I just called you guys "resources") can figure out how to do most anything.

regards all.....casey

 

[elevmike]

Casey,

Why in the world would I buy a 499 Dell when I already have bought a touch screen, and a PLC worth about 1500 ???

Just cant resist the urge for a new challange....

 

[CaseyK]

Okay Mike

Writing code for it will keep you off the streets for a few days (weeks). Now, if you would have gotten so AB instead of AD, multiply time and money utilized by "x", then you could "RANT", and we could post Eric's new smiley, again!

Actually, I'm surprised that you have enough free time to post, let alone program. You would starve around here. In a 30 mile radius there are six hospitals,four highrises, and maybe 6 other buildings with elevators.

But then, you would have enough time to get that roulette program wrote. Rather then red and black, I recommend red and green, so you can have a pair of pilot lights blink as the wheel turns.

anyway...enough for now.....casey



Judging by the poll, "HARDWARE" will be around a little longer!

 

[rdrast]

Re: Random Number Generator.

rdrast,

I'd really like to see that RND code. I want to apply it on an AD DL06. First game is roulette. (seems much easer code then cards etc..) RND generator picks number between and including 1-38, then just add or subtract bets.

Thanks, Mike.

Mike, you asked for it, you got it.

This is a basic 16 bit XOR-Tap random number generator. The original idea came from Don Lancasters CMOS Cookbook, way back when. I've since applied the same basic generator for SLC/PLC's, NAIS FP series, TI505's, and Simatic S7's. The attached one is for an SLC500, and runs under the emulator.

It eventually generates a random from 0 to 100 (IIRC), and populates a data table with the number of hits so you can verify the distribution.

 

[elevmike]

rdrast,

Bummer, I dont have AB software. It's not that important, but if you get a chance, maybe you can print it out to a pdf file and repost the the pdf file.

Just in case, you can create a pdf file by downloading a utility here: http://www.pdf995.com It installs a virtual printer on your PC. When you print a document, just select PDF995 as the printer. Its a freebee so every time you "print" it opens a promo web page. Other than that it works great.

It's just for fun, so dont go way out for it.

Thanks, Mike.

 

[Pierre]

Hummm!!! I voted and check the results. Wow, only one vote for YES then it could only have been me.

Sorry i read ...future of existing...

Not today. Heck no.

But the sooner the better. A few steps are needed before it comes to life.

Some have to do with where Bill is going and some with AB.

Now if only I could change myavatar

 

[CaseyK]

Pierre:

I enjoyed seeing your avatar. I used to see the blue screen of death a lot, then I figured out how to eliminate it. I won't touch Steeplechase PC software anymore.

I told a large maunufacturing facility purchasing a new machine that the Steeplechase software was a waste of time and money, was not practical, and if they really wanted to run the assembly line properly, then we needed to scrap the control system and install a 9030 for $3,000, and ask for the $36,000 back from Steeplechase, and keep the desktop for solitare. I didn't want to have to contine to try learn how to program it, or figure out if it could even be loaded and ran in most pc's. So I got all the plc projects.

A few months after I was gone, the machine showed up, and it still had Steeplechase, blue screen of death and all. Steeplechase didn't run, machine didn't run. After a year of the machine manufacturer and Steeplechase engineers trying to make it run, the multi-million dollar project was wrote off. Five years later, the machine once again "Lives". The two robots run independently of everything else, and three Micro 90 plcs run the conveyor lines and other equipment. And no blue screen of death. Since the computer WAS NOT company standard, it can't be used or networked. It sits in the maintenance break room, for "solitare" use only!

PC's in charge??? Perhaps some day. In the meantime, PLCs RULE! And I am willing to wait for the "elevmike roulette 1.3" software package, expected to be released on a PLCs.net thread soon! (With royalties to our main man, Phil, naturally.

regards..........casey

PS

After pondering this a little bit, given the choice between Steeplechase and Allen Bradley, I'd become the #1 AB fan!.

PS2

I have used GE's Cimplicity without any major problems, but think it is too pricy. Can buy a lot ofPLC racks for one software package.

PS3

I am really impressed how many times you can edit! Thanks Phil!

 

[elevmike]

Casey,

I'm still trying to figure out the Random Number Gen. (1-38). I've search the site and read the threads on this but it all about AB stuff, and I only have GE (Cimplicity ME) and AD (Directsoft), and some old Omron (LSS2) equipment and software. I would much rather prefer using an AD. The rest is easy, I just need an RND function. Now I cant spend a lot of time on this now because we just got P.O.s for a couple of BIG projects. So if anybody can help me with the RND for an AD I would surly appreciate it, and will post the end result, (beta's also) on this site.

Later, Mike.