P R O T O T Y P E         S C A D A
Supervisory Control and Data Acquisition
with Telephone Dialing Capability

1 - Background
2 - A Review of Relevant Management Concepts
3 - Proactive Management Style and Information Process
4 - The Technical Scheme
5 - Project of the Graduating 5th Year
BS Computer Engineering

1 - Background.        

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  • The principles surrounding this project are similar to those that inspired the "Hands-on Course on Data Communication between the PC and Plant Processes".

  • One might say that this project is a showcase that proves the applicability of that course.

  • I am repeating the background of that course in the next few paragraphs.
    (please click here to by-pass text)

    1. Head Offices in the Philippines normally run high level Management Information Systems.

    2. The same company's manufacturing plant, likewise, take pride in the state-of-the art control system, "distributed control systems" (DCS) and similar systems.

    3. For the heck of it, ask the question: "what is your current production cost per kilo of product?". It was "X" pesos yesterday as of 12:00 noon. "No, but I am asking what is it now?"

    4. The frustration becomes even more pronounced if you ask the question: "what is the rate of change of the deterioration in production cost as a consequence of the quality of raw materials delivered but you are forced to use to fill the demand?".

    5. One element in the solution to the lack of TIMELY, RELEVANT and ACCURATE information is to make the head office computer communicate with the plant process control computer at real-time.

    6. But one may say, there are an awful lot of software and hardware solutions out there.

    7. In this country, one pays a fortune for such solutions, in addition to maintenance contracts to be implemented by expats at expat billing rates and conditions.

  • Let us discuss some management principles in the next section.

2 - A Review of Relevant Management Concepts.        

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At this point let us review some relevant management concepts

  • Many organizations review their operations on a periodic manner, and this accepted practice is perfectly alright.

  • During review meetings, executives would report one after another, their target, their performance, and the variance between the two.

  • If the variance is favorable, the gain to the company is the accumulated variance over the period from the time of the last reporting until this latest review.

  • What has just been reported is "history" - favorable history!

  • On the otherhand if the variance is not favorable, the company has just been informed that it has incurred LOSSES, or maybe a reduction in its expected profitability.

  • This, too, is history - an UNFAVORABLE one.

  • There is nothing one can do about history. It just IS!.

  • A "proactive" organization is not one to be dished out history.

  • It must be given the opportunity to steer or direct its path so that a change in the operation of the company may be implemented before unfavorable conditions accumulate into considerable amounts.

  • In the next section, I will describe some proactive ways with the use of data communication as I describe here.

3 - Practive Management Style and Information Process.        

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  • The first element in a proactive management style is the availability of an information process that "points to a direction at the time that it happens".

  • The traditional reporting of "variance" during management reviews does not provide this direction at the time that a corrective action must be implemented.

  • I am recommending the shift to the concept of rate of change of variance.

  • One might be tempted to suggest that the reported variance be simply divided by the elapsed period and voila!, one has rate of change of variance. And that suggestion is correct, unless one starts to quantify the unfavorable (if, indeed, it is) effects that have been experienced between the review times.

  • I am further recommending the following

    1. Provide communication tie-ups between the manufacturing process equipment and devices with a central PC.

    2. Construct algorithms within the PC that would calculate the effects of each operating process parameter to the unit cost of production.

    3. I put great emphasis on unit cost of production since this is one important component in the selling price.

    4. Calculate the rate of change of production cost at real-time.

    5. Provide "high" and "low" alarms. If the rate of change of production cost increases more than a certain amount per unit time, notify the Shift Superintendent and/or the Plant Manager, because something DESERVES attention. If it is the other way around, it also deserves attention because, maybe, the quality of the product might be at jeopardy. But do not set aside the possibility that, maybe, just maybe, something is being done right and that it could be documented to improve operations.

    6. Notification can be done in many ways, such as, (a)the computer dials a pager and sends a code, or (b)the computer dials a mobile phone to send a text message, and so on. The possibilities are enormous.

    7. There are many other conditions in an operating plant that deserves the attention of other officers of the organization. For example, a plant has accepted orders that require that it runs at full capacity 24 hours a day. An interruption may lead to liquidated damages if not effectively managed. This is especially true if the procurement of components, and the like, require a specific approvals process and a snag is encountered at one of the steps. On the other hand, the Chief Operating Officer could effectively provide the needed guidance without delay and too much adrenalin being used up.

4 - The Technical Scheme.        

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  • The technical scheme is relatively simple and unambiguous. I use it a lot in my lectures to introduce a slightly different management approach.

  • The configuration is as follows

    1. A "Red Lion Digital Temperature Monitor" is hooked up to the PC through their respective RS232 ports.

    2. The PC reads the device every 15 seconds, converts the readings by some algorithm to cost per unit of product.

    3. A "C-language" program manages this whole transaction, dynamically plots the results, and stores data on disk for further reference.

    4. When the "unit cost" parameter crosses the manually adjustable "high" mark, the computer initializes a modem, dials my pager and sends me a numeric code about the condition that is now prevailing.

    5. A similar action is undertaken by the PC when the "unit cost" parameter crosses the "low" mark, except that it sends my pager a different code.

    6. Notification could be done through the internet, or through a mobile which may be anywhere in the world, and so on. The possibilities described here are just the proverbial "tip of iceberg".

5 - Project of the Graduating 5th Year BS Computer Engineering.        

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  • During the planning session of my 5th year BS Computer Engineering class of school year 2000-2001, they decided that they would automate the operation of our laboratory, Room F311.

  • Since these ladies and gentlemen were to go into the job market in less than a year, I added the management information aspect described above.

  • This project was a success and is documented at the URL below

    The Supervisory Control and Data Acquisition (SCADA) Project.

  • The pedagogical method employed also earned the "Dean's Award for Teaching Innovation".