Casually surfed over to ISA with a thought of joining - until I saw that the
standards will cost you USD9.50 each and only available in batches
(subscriptions) of 10. That is besides the membership fee.
At least they tried to hide it by stating that members could buy an
unlimited amount of subscriptions. Wow, great, way to go.
This reminds me of profibus. You go to these instrumentation shows and they
have all different OEM equipment hooked to this silly purple cable. "Great",
I thought. Until I tried to hook a Siemens HMI panel to a Mitsubishi
Q3-series via profibus DP. Last OEM quote was Euro77000 to write a driver
for the Siemens PROFIBUS panel. So much for open source and
interconnectivity. Like ISA, it's all about the money.
Is getting the standards the only reaon you can think of for joining?
Can you see the the standards in libraries?
Are people supposed to work for no money?
Did you fix the Siemens - Mitsubishi interface problem? Did you get paid?
There is a reasonable discussion to be had over whether standards could be
developed and distributed at lower cost of course.
There was a US senator in the early days of railroads who said something
along the lines that wherever there was a change in railway gauge, a town
appeared and commerce flourished. Just like Profibus.
If all you want is a discount on purchase of standards, books, or
training, (that other people write) you can do the math and decide if
it is worth it.
If you want to paticipate in the committees that write the standards
and do other things for the industry you should join.
The problem with the ISA, profibus and everything else is it is
tainted to the folks and companyies that are inside. The scary part is
that these old engineers really think they know controls. They do, if
all you want to do is fancy twist on PID.
They do not know shit about the software underlying products. The
state-machine, kernel, executive, or RTOS is what makes or breaks a
control system. The problem is embedded linux is leaving green-hills,
allen bradley, Wind River and company behind in decades of old
If you want to learn about real controls, you have to dig deeply into
the underlying assemble and ansi-C code that runs on microprocessors,
DSPs, and FPGAs. It is there you will really learn about controls,
determinism, multi-threaded process etc etc. The PLC vendors push
ancient controls systems build on pathetic state machines or RTOS, and
the obstruficate the concepts of controls.
The SCADA vendors are even worse. The good news is now that the US
government, NSA, cia, and fbi are looking closely at all of this
expensive bullshit, they are realizing that only embedded linux can
build secure control systems with modern functionaliity. Do not look
for the vendors of these old-tired systems to make their software
secure. They could not do it, if they tried. Time and again, I build
devices and interfaces to 'sniff' out old-tired proprietary protocols
that are mostly clear text. If they bother to use encryption, it's
I teach technician how to code in the assembler that is available on
the controller, so they can understand the native assembler language
and build modular programs that are portable. You can map the 'ladder
logic' elements it block of assembly code. Once you do that, you can
get all sorts of hardware to run controls systems on, make controls
system distributed on top of RTlinux and purchase hardware anywhere.
At that point, you can use a real programming language like ansi-C.
Don't get me wrong, if a company wants to pay me money to develop
controls code a particular plc or scada system, then that's OK.
However, when I show them code that runs on linux based pcs and the
same code or it's assembler derivative on a demo board form a
semiconductor manufacture (and orders of magnitude cheaper prices)
they rarely choose the proprietary path.
Do look to the ISA or Profibus or devicenet(a real poor implementation
of the CAN bus) or any of their associations to really teach you
anything other than how to use their products and code to be a slave
to their financial aspiriations.....
Dude, that's not engineering, that's what uneducated technician do...
Real engineers can code and solve problems in a variety of languages.
My last major project involved writing ansi-C code to verify the logic
and calculations of PLCs. I has to reorganize their thoughts to get
the software happy for all of the 'regulators'. The really sad thing
is I told them the solution was correct and operable, but not
optimisitc. Now they want it optimized. I told them the only way to do
that is with embedded linux. I offered hardware for free(only cost me
less than a thousand bucks) all of the software free. They are still
thinking about my offer.
The are senior members of the ISA......
Run, don't walk, to linux, ansi C and native assembler before you
really think that ladder logic programming is robust.
PS Ladder logic is good for graphical representation, and simple
tasks. It is not a robust solution for complex problems. If you really
want tight control aka a high speed assembly line, you have to get
into the guts of the RTOS running on the processor, to do things so
that 'old_folks' say, 'how did you do that'.
A computer science degree never hurts..........EEs can not code for shit!
Let me repeat this little story a professor at Purdue told us in a
controls class back some time ago--seems a government
commissioned at study, I think it was in Russia, to look at industry
and determine how much benefit could be obtained by applying modern
control methods. Sorry but the details have faded a bit in my memory.
Anyway, the study reported out that about 99% of the control processes
they examined were at or near optimal using PID controllers. Seems
those old boys in the plants, while not really understanding everying
that was happening, managed over time to tweek the controls to about
as good as was possible. I think the point of the story was as we
study modern control we should retain a bit of humility, because all
that neat stuff we learn is only required 1% of the time.
Those Russians must have done well, or they are lying through their teeth,
but they have a point. From what I can tell, a large portion of controls
are either poorly tuned, or, in many cases poorly constructed. It isn't
that PID won't work well. It is that PID isn't being used as well as it can
be. Of course, they may not have looked closely enough at the systems being
controlled, and may have a different viewpoint of "optimized". If they are
talking about just controlling a simple flow rate with a valve, then that is
one thing. PID does not do whole plant optimization.
OK, I'd agree with both points, most controls are simple and most can
be performed adequatedly with stochastic and empiracle methods. So why
Modicon, or other proprietary controls vendors, like those promoted by
thousands of dollars for circuits and microcontrollers, that you can
purchase less than $99 dollars per board, off the shelf? Why used
crippled, deficient, security proned software from vendors that build
software development programming environments from crippled vendors
such as microsoft? The same rings true for SCADA packages, when you
can use linux, and get security enhancements, that work?
If 2 engineers build controls systems that perform adequately, but one
costs orders of magnitude more, which one would you deploy?
You cannot get inside of the software or the microcontroller to see
what's actually going on (microcontrollers have wonderful standard
interfaces called JTAG, you should learn about JTAG if want to be
useful in the future) and deal with a myriad of issues including but
not limited to security problems?
Which engineer would you hire? Which engineer makes more profit? Which
engineer can actually secure the critical controls infrastructure in
Get real.....Get educated, and for god's sake dump microsoft,
allen-bradely, modicon, etc etc, and go back to being a real
engineeer.... Use circuits designs that work, and software that you
write. Who knows, you may actually enjoy being a real engineer,
instead of pimping for the ISA and the other vendors, that do not give
a damn about the average working engineer....
Well, I can give a couple reasons. I want to make sure that the system I
buy today is going to composed of readily available parts, that those parts
are designed properly, that the machine interfaces work in a very standard
method, and that there is a user interface that doesn't look like an
afterthought. I want a uniform ladder logic system, a good alarm system, a
great data historian, and the ability to have my systems communicate with
one another easily. I also want an organization to stand behind their
product with an unlimited liability agreement. For giggles, I also want to
know that whatever I buy today will be superseded with a better, more
capable system in the not too distant future.
Sure, I can come up with engineers who like to play with microprocessors and
such. I can even find a few good ones. What I typically would need,
however, is someone who understands the system dynamics of a large scale
chemical process, and knows which units to put where in order to get the
best control possible. If these companies have already adequately invented
the wheel, then it saves me the trouble of doing it.
I don't want someone to cobble together a system of $99 boards and a bunch
of PC's. I've dealt with those boards and those systems. It is at best a
crap shoot as to whether that comes our right. With a good engineer, it
works great, at least the parts he's good at and while he's around. With
two good engineers, I can end up with a maintenance nightmare. With a poor
engineer I'd be better off with manual valves.
As far as which engineer I'd employ, I'll look at the long term economics.
If I have to have low level programming done with each and every loop, I'd
quickly find that the cheaper hardware takes longer to install, test, and
verify. I'd also find that making sure I can get the right parts if it
breaks gets expensive in a couple years. I'd have to constantly worry that
whatever code was written was indeed correct. I'd also have to make sure
that the code was well backed up and that I have a staff who can work on it.
The expensive engineer who called a vendor, ordered a dozen of this, and a
dozen of that, knowing that each will fit together and perform properly on
the process, and inside of a few weeks or months has the whole thing running
starts to look very good.
Personally, I don't care if the system uses MS or a proprietary system. It
has to work, completely, and quickly.
I have seen a few plants that were controlled by $99 board cobbled
together. They may have worked for a while, but soon the plant was
mess. Pretty soon these on-the-cheap systems were replaced by real
control systems, using DCSs and PLCs, supplied by companies that had
been in the business for years and will continue to be around. Most
plants expect a control system to work for years without interruption,
to be expandable and upgradable while still operating the plant, and
for the vendor to have knowledgable applications engineers who have
experience in the industry.
I have never seen a control system not function because the programmer
didn't get involved in the low level software or used the wrong
operating sytem. I have seen many systems not operate properly because
the control engineers did not have sufficient knowledge of the process
and of basic process control, or who did not fully understand the
needs of the operators.
The most successful control engineers (measured by results in good
plant operations, were chemical engineers or others with appropriate
knowledge and experience in their industry, including experience that
went far afield of just process control and included process design
and operations. Knowledge of programming may allow you to make some
elegant looking code, but it isn't enough to allow you to make a
process plant run efficiently and safely.
Hey, the price one pays for materials does not reflect on the quality
of work. Allen Bradley et all purchase material for a far lower price
than I can. But the look of their work is top notch, but, expensive
when you see it. Just because you pay a low price for something does
not mean that the installation work has to look poor. And It's the
same microprocessors and electronics the big boys use, minus the price.
your conclusions are illogical and non-sequitor...
Obviously you have lead a sheltered life....
Yes these are prerequisites we all assume of each other I could
cheaply say these things about others, but, these issue are
irrespective of the underlying technology, which, is what I thought
the discussion should focus on. I'm assuming you guys are competent
engineers. Most definately I am, PE et al.
Dude, you finally said something I agree with. I do indeed have a
petrochemical degree, and EE degree and a masters is computer science
and a PE to boot (yes I passed the piss-ant of test concocted by the
ISA, in less than 2 hours for an 8 hour test. (you know first to leave
kind of guy, in a room full of 800 wannabees.......)
PE or a other degrees do not mean anything. My field experiences, and
my time DESIGNING solutions and not perveying solutions that other
came up with, are what matters and works best.
On Tue, 15 Jun 2004 18:50:58 GMT, the renowned James
The $99 board may have a better, faster chip of equal quality, however
it is probably missing all the packaging, EMI protection and other
items surrounding the chip that make it reliable in an industrial
environment. This stuff *does* matter, and the more of it you have
around, and the longer you expect it to work, and the higher the costs
of problems, the more it matters.
"it's the network..." "The Journey is the reward"
firstname.lastname@example.org Info for manufacturers: http://www.trexon.com
Now here we go again taking things out of context. If you assume that
Analog IOfrom a major vendor, for example, is better that Analog IO
uniquely implemented you may be right or wrong. Most boards from
vendors such as Allen Bradley, Siemens etc, use common grounds. I
often use a seperate grounding systems for Analog IO for higher
accuracy needs. Vendors of systems make many, many economic trade offs
that you are un aware of or incorrectly make assumptions about. I
DESIGN what it needed, so don't assume that just because I spend $99
for something you pay thousands of dollars for, that my system is
I'm currently design a datalogger for a niche market. Surge protection
is a big concern as most the 'big name vendors' in this space have
problems with surge. I have test about 15 of the best modules made,
and selected the one that performs the best. It happens to be on of
the most expensive surge protection module anywhere for this
Please do not assume my work is inadequate. My work is elite, and 99%
of my business is from broken or disfunctional situations where folks
have already spend rediculous sums of money. Parts and materials are
cheap. Really good engineering is a lost art, especially here in the
States... Excellent engineering may or may not use commercial big-name
vendor materials. It all depends on what you are familiar with and if
you want to save money, or be proud of a expensive big-vendor name.
It's your call, and your employeer's bottom line. Don't bitch one day
when you wake up, and your employeers has hired a bunch of kinds from
a foreign country, because they'll be most likely to use embedded
linux, and save their employer lots of cash on material your payroll....
On Tue, 15 Jun 2004 21:31:24 GMT, the renowned James
Whoah... that's really not too likely, IMHO.
No, I assume that such systems often have one or more hidden flaws,
either inherently or when the typical customer applies them. In
particular, bespoke designs often skimp on important stuff that's
expensive in one-offs but reasonable in the higher volumes that can be
moved through a national or global distribution network.
Your situation may well be an exception, but in general I think it's
better to design robustness into an instrument or control and not
depend on fixes kludged together such as surge protection modules or
external analog galvanic isolators.
Doesn't take much downtime to eat away any supposed "savings" of
capital cost in most production situations. Components are cheap, but
good engineering is definitely not-- electronics designers experienced
in the industrial environment, analog and digital, and control domains
are rare, and also functionally adequate (not necessarily pretty)
packaging can be very expensive in small quantities.
I am in a somewhat foreign country to you (Canada) and happen to be
designing instrumentation for more than one American company at
(approximately) this very moment. FWTW. Embedded/realtime Linux seems
like a fine idea to me. ;-) I wouldn't mind monitoring something with
Winxx but attempting control might be way too exciting for my tastes.
Oh, and a project I just completed came about because the company
hired a young engineer from overseas who messed things up fiddling
around at the component level where he did't know how much he didn't
know. Medical-related too. 8-( Very costly.
"it's the network..." "The Journey is the reward"
email@example.com Info for manufacturers: http://www.trexon.com
Hm, PLC vendors pay semiconductor companies less that $10 for the
chips. For persons that do not want to design an actual circuit board
to test something, or deploy a product rapidly, you can often purchase
modules or development boards. The is not low quality about this, as
Allen Bradley, Automation Direct, Seimens (who is actually a
semiconductor company too) etc etc use this approach. You'd be
suprised at what they wrap inside of a nice enclosure, and add 3
orders of magnitude to the price, and sell to chumps you the best of
It's your money, or the lack thereof. If you follow the dribblings of
the ISA, you'd think the controls industry is in recession. No, it is
not, it booming, just not with the deployment of overly expensive big
name vendors. The DOD and many other groups are droping COTS control
equipment, primarily for security reasons, but also for costs. And new
paradigms that encompasse traditional approaches to controls and have
many new features, are displaysing these antequated technologies.
That's why the ISA is gloom and doom, and guys lke myself consult
directly at excellent consulting rate, and you guys are continuing the
misery of traditional ( and currently unemployed) controls engineers.
You know what, why don't you attend a semiconductor conference and
tell TI their equipment sucks? Or pick another semiconductor company,
like Motorola, that has been building their own control systems for
decade and have left the product and it's expensive prices to keep
racking in thousands of dollars when a $30 and a real engineer would do?
Um your statements are self_incrmiminating of your personal skill set.
Hey, now you are showing original thought. I typically fix stuff
behind vendors and ladder logic guys, because I can look deeply into a
Let's take sampling rate as an example. If you have a problem and you
bring in data, via a plc, how fast (how often) can use sample? What
happens when you find a problem that the vendors best PLC does carry
the necessary number of bits, at a fast enough sample rate?
Duuhhhhhhhhh, didn't know that such problems existed...........
WE'll learn about DSPS and sampling rates on analog sensor technology
and you can begin to see how traditional plc vendors are ok for normal
problems (although their solution is expensive) and fail to grasp or
work at all in complex situations.
This "old engineer" has learned that accuracy in detail is of utmost
importance in any control system whether it be relay based or high-tech.
The misplacement of a single wire in relays, a single comma in code, or a
single bit in a packet invalidates the entire system. That is why I am
extremely suspicious of any code writer, programmer, etc. whose written work
is full of spelling mistakes and other sloppiness.
"If you want to learn about real controls, you have to dig deeply into the
underlying assemble and ansi-C code that runs on microprocessors, DSPs, and
FPGAs. It is there you will really learn about controls, ..." Actually,
no. What you learn there is about programming. If you want to learn about
controls, you did deeply into Piping and Instrument Diagrams, and the
behaviour of process equipment, the requirements of operators and their
interface, and the various codes governing safety and reliability. The rest
"I told them the solution was correct and operable, but not optimisitc..."
Does that make the solution pessimistic? Now I know that many details are
important, but I have never before been concerned with the emotional state
of a program.
Dude, it's email on a discussion group. I use all sorts of ethnic and
illiterate gestures, often to make a point. If thought a spell check
was necessary, I'd configure it to run automatcially. In this forum it
ain't, so get over yourself and your condecending ways..........
I'm not asking you for work, I have plenty and I'm designing new
Wrong! yes programming is a necessary tool, and if you are going to
write ladder logic programs, you'd be doing yourself a hugh favor and
learn to code in several other languages, including assembler and ansi C.
The underlying RTOS defines how your PLC code will run and operate. If
you are only closing a valve that has to take at least 5 seconds, but,
no more than 8, for process or water hammer considerations, then
ladder logic is OK.
If you are controling the guidance system on something that has
complex delivery and travels in excess of mach4, then the underlying
timing, provided by the RTOS, is critical. You cannot leave this to
VXworks (er I mean allen bradely).
You know, I assumed we were all going to be charatible and consider
that each other had mastered the traditional craft of controls. If
someone indicates they need help, or are deficient, then you'd have a
valid point. Dude, I'm what they call 'elite'. I assume the good ole
boys (and many of my friends are indeed good ole boys) are damn good
at what they do. Elite is more like magical. I do things that other
controls engineers say, "how'd you do that?" As long as we stay polite
and friendly, I do not mind showing folks a better way, if they ask.
Dude optimistic is a mathematical term. There is not place here for
childish emotion. I just assumed this of everyone?
Pessimistic equated to outright failure or a filter that denys most
things, in a mathematical sense. I hope we're not exploring the realm
of human emotions, if we are, count me out of here!
PS, If you are ever so lucky to have me on your payroll, then you can
bitch about spelling and grammer. At that point, I'll spend the extra
energy on a
pretty format (dude this is a programming term not an emotional schism)
But it's fun jerking their chains. Actually, it's an experiment: I'm
trying to guess what kind of fool he is. I've met this type before. He
believes he is a super genius and that everybody else is an idiot.
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