Belajar PLC dan SCADA

Just another Blog about Programmable Logic Controller & SCADA.

GE Fanuc makes PACSystems RX3i Controller redundant

Written by Kang Abu on 10:21 AM


June 2, 2009 - GE Fanuc Intelligent Platforms introduced its scalable high availability solution for the PACSystems RX3i controller. By combining essential processes and capabilities onto one platform, the PACSystems RX3i controller is one of the most powerful, scalable, flexible, and efficient means to increasing productivity. It now adds high availability to its multi-domain functionality along with logic, motion, HMI, and process control.

Built on a synchronized hot-standby redundant control platform with transparent bumpless process switchover and easy configuration, PACSystems High Availability facilitates continuous uptime in essential applications.

GE Fanuc’s PACSystems RX3i High Availability is designed to keep essential systems running efficiently and reliably by connecting two independent controllers on our proven RMX reflective memory technology link providing up to 2 Mbytes of data synchronization. If an event occurs with the primary controller, the control functionality is automatically switched over to the redundant controller for continuous operations. It serves the needs of applications where continuous uptime is essential to profitability, where bottlenecks must be avoided, remote locations where time and cost to repair is extended, and operations where work stoppage means lost production. It can be found in areas as diverse as protecting critical information in data warehouses, ensuring water quality at water treatment plants, and keeping the power on for hospitals and surgery centers.

With PACSystems High Availability, operations globally are delivering results for a sustainable competitive advantage:

  • Minimized downtime through robust, dual redundancy sync link
  • Increased productivity due to fast, powerful synchronization and the ability to maintain individual system components without interruption
  • Maximum protection of investments with flexible, scalable, open architectures
  • Time savings and reduced engineering costs with easy configuration and quick startup and maintenance
  • Increased data integrity through advanced memory error checking and correction (ECC)

    PACSystems RX3i offers true dual redundancy data synchronization with dual modules and dedicated, redundant links to one another. They operate with virtually no overhead added to the control application.

    GE Fanuc’s unique, patented Redundant Memory Xchange (RMX) modules, based on reflective memory technology, synchronize the system at the beginning of the input scan and the end of output scan each logic scan execution to keep the controllers in lock step. Furthermore, the systems can be located up to 300 meters apart to so that any localized event affecting one system does not affect the other.

    PACSystems High Availability is designed to operate as a single, complete system, therefore eliminating the complex preparations typically associated with synchronizing and data transfer.

    Configuration is made easy with a Redundancy Wizard that guides the user in setting up shared data and I/O for both systems in a matter of minutes.

    PACSystems’ high speed memory sharing enables CPUs to be synchronized at 2.12 Gbits/second and multiple devices to transfer large amounts of data, up to 2 Mbytes, over a fiber optic deterministic network at speeds up to 20 times faster than Ethernet. The use of fiber optic connections allows users to easily operate in high-noise areas and cover large distances in real time.

    “The PACSystems RX3i High Availability really maximizes return on investment,” said Bill Black, Product Manager for Controllers at GE Fanuc. “With minimized downtime in process, increased productivity with fast powerful synchronization, reduced engineering costs with easy configuration, and increased data integrity, all in the smaller footprint of the RX3i, customers really see the power of the system.”

    Seamlessly integrated into the system, the high availability continues to build out the incredible value of the entire PACSystems RX3i programmable automation controller.

    The PACSystems RX3i High Availability is available immediately.

    About GE Enterprise Solutions
    GE Enterprise Solutions elevates customers' productivity and profitability with integrated solutions using sensors and non-destructive testing; security and life safety technologies; power system protection and control; and plant automation and embedded computing systems. Enterprise Solutions' high-tech, high-growth businesses include Sensing & Inspection Technologies, Security, Digital Energy, and GE Fanuc Intelligent Platforms.
    About GE Fanuc Intelligent Platforms

    GE Fanuc Intelligent Platforms, a joint venture between General Electric Company (NYSE: GE) and FANUC LTD of Japan, is an experienced high-performance technology company and a global provider of hardware, software, services, and expertise in automation and embedded computing. We offer a unique foundation of agile, advanced and ultra-reliable technology that provides customers a sustainable advantage in the industries they serve, including energy, water, consumer packaged goods, government & defense, and telecommunications. GE Fanuc Intelligent Platforms is a worldwide company headquartered in Charlottesville, VA and is part of GE Enterprise Solutions.

  • Source: http://www.automation.com

    S7-300/400 CPUs: Temperature Recording in the S7-CPU by Means of Pt100 Resistivity Thermometer and SITRANS TK-L Measuring Transducer

    Written by Kang Abu on 3:52 PM

    Problem

    Almost everywhere where products or materials are processed or worked, the temperature has a decisive influence on the quality of the final product and the course of the process respectively. It is thus necessary to record the temperature, to interpret its influence and to specifically react to changes in temperature using control technology.

    Solution

    The device combination of SIMATIC products and SIEMENS temperature sensors including measuring transducers is an excellent solution to the mentioned problem. In this application, a Pt100 sensor records the temperature of a measuring object and a SITRANS TK-L measuring transducer converts the sensor's measuring signal into an injected current which is supplied to an analog input of the compact CPU. The current temperature measurement value is displayed both numerically and as a bar chart on a TP170A touch panel.

    Using the special STEP7 application software, which you can download (see below), it is additionally possible to ...

    • define seven temperature ranges which are displayed on the touch panel and represented by DO bits. These bits can be used to trigger various user actions.

    • display limit temperature violations requiring acknowledgement, react to them (in the program) and acknowledge them.

    • provide the last insufficient or excess temperature with a time stamp.

    The WinCC flexible configuration of the TP170A is integrated in the STEP7 project. The user interface languages German and English can be selected.

    Downloads

    Content of Downloads

    Download

    Documentation (German)
    Application Description
    23541638_Temperaturmessung_DOKU_V20_d.pdf ( 1094 KB )
    Documentation (English)
    Application Description
    23541638_Temperaturmessung_DOKU_V20_e.pdf ( 1044 KB )
    Code
    STEP7 Project
    23541638_Temperaturmessung_V20.zip ( 3007 KB )

    History

    Version

    Modification

    07/2002 First edition (V1.0)
    08/2006 Second edition (V2.0) complete revision and update

    Filter criteria:
    Hardware platform: SIMATIC S7-300/S7-400
    Software: STEP 7
    Entry contents: Application Examples

    Video Tutorial: The High-Level Language S7-SCL

    Written by Kang Abu on 7:35 PM

    Topic
    SIMATIC software is the integrated system environment for all SIMATIC systems and provides you with the ideal tool for every task at each phase of your project for optimizing your engineering workflow. The SIMATIC software offers a wide choice of programming languages that support you in the implementation phase. From these various languages, therefore, it is possible to select the language most suitable for each task to be mastered in an automation plant and thus keep time and costs down to a minimum. Thanks to the higher language constructs supplied with it, S7-SCL is suitable for calculations and data management algorithms.

    Content
    Based on a brief comparison of the programming languages included in STEP 7 Professional, we show you the decisive advantages of the high-level language S7-SCL that is similar to Pascal. We look at a number of language constructs in detail and demonstrate on the fly how you can implement complex algorithms quickly and easily with S7-SCL. This module shows in graphically animated scenes

    • the customer benefits that the tool provides for each relevant project phase,
    • the basic functions of the tool
    • a live programming and debugging sequence in S7-SCL.

    Presentation
    The following properties are contained in all technically-oriented demonstration systems:

    • All graphic animations are explained by a spoken text which has been read by German, respectively English native professional speakers.
    • The respective sections of the demonstration system can be clicked on by means of navigation elements. You may, for example, repeat any section any time.
    • Continuative links and support pages have been integrated.

    The following picture shows the home page of the demonstration system.

    Downloads

    Content of Downloads

    Download

    Demonstration System "The High-level Language S7-SCL" (German)
    Duration of Animation: 14 min
    Download size about 36 MB
    21062480_S7_SCL_v20_d.exe ( 36332 KB )
    Demonstration System "The High-level Language S7-SCL" (English)
    Duration of Animation: 14 min
    Download size about 35 MB
    21062480_S7_SCL_v20_e.exe ( 34733 KB )

    Just load the EXE data file at hand on your computer and start it with a mouse click. You may as well start the EXE data file directly out of your browser.

    History

    Version

    Modification

    12/2004 first edition
    09/2008 Update to version v20: correction for the correct execution of the demonstration system on PC/Notebooks have been made. The content of the demonstration system has not been changed.


    Video Tutorial: Testing and Commissioning Functions

    Written by Kang Abu on 7:33 PM

    Topic
    SIMATIC software is the integrated system environment for all SIMATIC systems and provides you with the ideal tool for every task at each phase of your project for optimizing your engineering workflow. The SIMATIC software gives you optimum support in the “ Testing and Commissioning“ phase with practical testing tools and diagnostics functions.

    Content
    Here we demonstrate the practical testing tools and diagnostics functions of the SIMATIC Manager.By running through typical commissioning tasks we show the practical application and benefit of these functions for commissioning hardware and software. This module shows in graphically animated scenes

    • the customer benefits that the tool provides for each relevant project phase,
    • the basic functions of the tools
    • live test sequences.

    Presentation
    The following properties are contained in all technically-oriented demonstration systems:

    • All graphic animations are explained by a spoken text which has been read by German, respectively English native professional speakers.
    • The respective sections of the demonstration system can be clicked on by means of navigation elements. You may, for example, repeat any section any time.
    • Continuative links and support pages have been integrated.

    The following picture shows the home page of the demonstration system.

    Downloads

    Content of Downloads

    Download

    Demonstration System "Testing and Commissioning Functions" (German)
    Duration of Animation: 25 min
    Downloadsize about 61 MB
    21064135_Test_Commissioning_v20_d.exe ( 61034 KB )
    Demonstration System "Testing and Commissioning Functions" (English)
    Duration of Animation: 25 min
    Downloadsize about 61 MB
    21064135_Test_Commissioning_v20_e.exe ( 61465 KB )

    Just load the EXE data file at hand on your computer and start it with a mouse click. You may as well start the EXE data file directly out of your browser.

    History

    Version

    Modification

    12/2004 first edition
    09/2008 Update to version v20: correction for the correct execution of the demonstration system on PC/Notebooks have been made. The content of the demonstration system has not been changed.

    The Graphical Language S7-GRAPH

    Written by Kang Abu on 3:59 PM

    Topic
    SIMATIC software is the integrated system environment for all SIMATIC systems and provides you with the ideal tool for every task at each phase of your project for optimizing your engineering workflow. If there are sequential operations in a facility which are dividible into single processing steps, the automation solution will be considerably simplified with the use of sequence charts by means of the graphical language S7-GRAPH which can be applied easily and intuitively.

    Content
    Taking a technological example we demonstrate how to employ the S7-GRAPH engineering tool to realize a sequence chart.You will learn how a technological runtime structure can simply be turned into a runnable user program. This module shows in graphically animated scenes

    • the customer benefits that the tool provides for each relevant project phase,
    • the basic functions of the tool
    • live projection of sequence charts..

    Presentation
    The following properties are contained in all technically-oriented demonstration systems:

    • All graphic animations are explained by a spoken text which has been read by German, respectively English native professional speakers.
    • The respective sections of the demonstration system can be clicked on by means of navigation elements. You may, for example, repeat any section any time.
    • Continuative links and support pages have been integrated.

    The following picture shows the home page of the demonstration system.

    Downloads

    Content of Downloads

    Download

    Demonstration System "The Graphical Language S7-GRAPH"(German)
    Duration of Animation: 16 min
    Download size 34 MB
    21062148_S7_GRAPH_v20_d.exe ( 33545 KB )
    Demonstration System "The Graphical Language S7-GRAPH"(English)
    Duration of Animation: 16 min
    Download size 52 MB
    21062148_S7_GRAPH_v20_e.exe ( 51571 KB )

    Just load the EXE data file at hand on your computer and start it with a mouse click. You may as well start the EXE data file directly out of your browser.

    History

    Version

    Modification

    12/2004 First edition
    09/2008 Update to version v20: correction for the correct execution of the demonstration system on PC/Notebooks have been made. The content of the demonstration system has not been changed.

    The SIMATIC Manager

    Written by Kang Abu on 3:55 PM

    Topic
    SIMATIC software is the integrated system environment for all SIMATIC systems and provides you with the ideal tool for every task at each phase of your project for optimizing your engineering workflow. The SIMATIC Manager guarantees the smooth interaction of these projecting and programming tools by the integration of all these functions and tools, a common database and a consistent operation philosophy.

    Content
    Here you are informed on how the SIMATIC Manager meets these requirements. In addition a live demonstration ist staged which shows you how an automation project is created using the SIMATIC Manager. This module shows in graphically animated scenes

    • the customer benefits that the tool provides for each relevant project phase,
    • the basic functions of the tool
    • live projecting sequences of a real project.

    Presentation
    The following properties are contained in all technically-oriented demonstration systems:

    • All graphic animations are explained by a spoken text which has been read by German, respectively English native professional speakers.
    • The respective sections of the demonstration system can be clicked on by means of navigation elements. You may, for example, repeat any section any time.
    • Continuative links and support pages have been integrated.

    The following picture shows the home page of the demonstration system.

    Downloads

    Content of Downloads

    Download

    Demonstration System "The SIMATIC Manager" (German)
    Duration of Animation: 13 min
    Download size about 33 MB
    21064133_SIMATIC_Manager_v20_d.exe ( 33462 KB )
    Demonstration System "The SIMATIC Manager" (English)
    Duration of Animation: 13 min
    Download size about 34 MB
    21064133_SIMATIC_Manager_v20_e.exe ( 33619 KB )

    Just load the EXE data file at hand on your computer and start it with a mouse click. You may as well start the EXE data file directly out of your browser.

    History

    Version

    Modification

    12/2004 First edition
    09/2008 Update to version v20: correction for the correct execution of the demonstration system on PC/Notebooks have been made. The content of the demonstration system has not been changed.

    Additional Information
    The most important tools of the SIMATIC Software Engineering Suite have been carried out as graphically animated demonstration systems in order to present the seamless and consistent integration into the overall concept. The following table refers directly to the corresponding articles in the Application Portal.

    Title

    Link

    Visualization - The HMI Integration 21063246
    The Basic Languages KOP, FUP, AWL 21062590
    Communication with SIMATIC S7 21043576
    The Graphical Language S7-GRAPH 21062148
    The S7 Architecture 21064245
    The High-level Language S7-SCL 21062480
    Testing and Commissioning Functions 21064135

    Alternatively, you can order all single modules as a whole on the new Demo DVD SIMATIC Software (Faster from Design to Operation) 04/2008 in German and English free of charge via the internet.

    Please use the following link for the order form of the demonstration DVD:
    http://www.automation.siemens.com/infocenter/order_form.aspx?lang=en&tab=4&nodeKey=&docID=213

    The Basic Languages LAD, FBD, STL

    Written by Kang Abu on 3:53 PM

    Topic of the demonstration system
    SIMATIC Software is the integrated system environment for all SIMATIC systems and offers the user the perfect tool for each task and each project phase in order to optimize his engineering workflow. The basic software STEP 7 comprises the three languages LAD, FBD and STL which are in accordance with the IEC standard and which are learnable easily and intuitively. The three languages all possess an extensive stock of functions which can be applied to the entire range of SIMATIC Controllers.

    Contents of the demonstration system
    This demonstration system presents the three basic languages LAD - Ladder Diagram, FBD - Function Block Diagram and STL - Statement List. In doing so, we show the properties and possibilities provided by the various tools of the SIMATIC Manager for the implementation of a user program in the three language variants. In the form of animated graphical sequences, the module demonstrates

    • tthe customer benefits that each language and tool contributes in its respective project phase,
    • the underlying functional principles and
    • live configuration sequences with the editor functions of the SIMATIC Manager.

    Presentation of an animated demonstration system
    The following properties are contained in all technically-oriented demonstration systems:

    • All graphical animations are explained by a spoken text which has been read by German, respectively English native professional speakers.
    • .The respective sections of the demonstration system can be clicked on by means of navigation elements. You may, for example, repeat any section any time.
    • Continuative links and support pages have been integrated.

    The following picture shows the home page of the demonstration system.

    Downloads

    Contents of Downloads

    Download

    Demonstration System "The Basic Languages LAD, FBD, STL" (German)
    Duration of Animation: 21 minutes
    Download size about 45 MB
    21062590_KOP_FUP_AWL_v20_d.exe ( 45295 KB )
    Demonstration System "The Basic Languages LAD, FBD, STL" (English)
    Duration of Animation: 21 minutes
    Download size about 43 MB
    21062590_KOP_FUP_AWL_v20_e.exe ( 43464 KB )

    Just load the EXE data file at hand on your computer and start it with a mouse click. You may as well start the EXE data file directly out of your browser.

    History

    Version

    Modification

    12/2004 First edition
    09/2008 Update to version v20: correction for the correct execution of the demonstration system on PC/Notebooks have been made. The content of the demonstration system has not been changed.

    Additional Information
    The most important tools of the SIMATIC Software Engineering Suite have been carried out as graphically animated demonstration systems in order to present the seamless and consistent integration into the overall concept. The following table refers directly to the corresponding articles in the Application Portal.

    Title

    Link

    The SIMATIC Manager 21064133
    The SIMATIC S7 Architecture 21064245
    Communication with SIMATIC S7 21043576
    The High-level Language S7-SCL 21062480
    The Graphical Language S7-GRAPH 21062148
    Visualization - The HMI Integration 21063246
    Testing and Commissioning Functions 21064135

    Alternatively, you can order all single modules as a whole on the new Demo DVD SIMATIC Software (Faster from Design to Operation) 04/2008 in German and English free of charge via the internet.

    Please use the following linke for the order form of the demonstration DVD:
    http://www.automation.siemens.com/infocenter/order_form.aspx?lang=en&tab=4&nodeKey=&docID=213

    Demonstration System: SIMATIC Screencast Tutorials

    Written by Kang Abu on 3:47 PM

    Topic
    SIMATIC Software is the integrated development environment for all SIMATIC systems and offers the user the ideal tool for each task and each project phase in order to optimize his engineering workflow.The SIMATIC screencasts show selected multimedia-based scenarios of the software and provide an overview of the smooth interaction of the configuration and programming tools. The content of these Screencast tutorials is structured so the user can follow the introduced functions or configuration tasks successfully with his installed software.

    Content
    Using the following SIMATIC Screencast tutorials, functions, editors and option packages of the SIMATIC software are demonstrated live.

    1. Programming Languages LAD, FBD, STL
    2. Access Protection for Projects and Libraries
    3. Import and Export Functions of STEP 7
    4. PROFINET Topology Editor
    5. S7-GRAPH Sequence Charts
    6. Visioning and Comparison of Projects with SIMATIC Version Trail and SIMATIC Version Cross Manager
    7. Integrated Configuration with Catalog CA01 and STEP 7
    8. Functions of the Automation License Manager
    9. Premium Studio Installation

    Representation
    The activity-oriented screencasts each start with the information slides

    • Overview of the Scenario,
    • Benefits,
    • Underlying Functions
    • and Details View of the Live Sequences. Subsequently the Live-demo starts.

    Operation
    The screencasts can be played without further software. Simply load the respective ZIP file on your computer, unzip the EXE file and start this file via mouse-click. The screencast starts immediately and the operation occurs via the menu task of the player.

    Screencast: Programming Languages LAD, FBD, STL


    Figure 01: Start page of the screencasts "Programming Languages LAD, FBD, STL"

    Download

    Screencast

    Download

    Programming Languages LAD, FBD, STL (English)
    (approx. 5.3 MB, 5 minutes runtime)
    Programming_Languages_V52_e.zip ( 5344 KB )

    Screencast: Access Protection for Projects and Libraries


    Figure 02: Start page of the screencast "Access Protection for Projects and Libraries".

    Download

    Screencast

    Download

    Access Protection for Projects and Libraries (English)
    (approx. 5.4 MB, 7 minutes runtime)
    Access_Protection_V52_e.zip ( 5391 KB )

    Screencast: Import and Export Functions of STEP 7


    Figure 03: Start page of the screencast "Import and Export Functions of STEP 7"

    Download

    Screencast

    Download

    Import and Export Functions of STEP 7 (English)
    (approx. 8.7 MB, 13 minutes runtime)
    STEP7_Import-Export_Function_V52_e.zip ( 8417 KB )

    Screencast: PROFINET Topology Editor


    Figure 04: Start page of the screencast "PROFINET Topology Editor"

    Download

    Screencast

    Download

    PROFINET Topology Editor (English)
    (approx. 5.1 MB, 6 minutes runtime)
    PROFINET_Topology_Editor_V52_e.zip ( 5050 KB )

    Screencast: S7-GRAPH Sequence Charts


    Figure 05: Start page of the screencast "S7-GRAPH Sequence Charts"

    Download

    Screencast

    Download

    S7-GRAPH Sequence Charts (English)
    (approx. 5.9 MB, 6 minutes runtime)
    S7-GRAPH_Sequence_Charts_V52_e.zip ( 5865 KB )

    Screencast: Visioning and Comparison of Projects with SIMATIC Version Trail and SIMATIC Version Cross Manager


    Figure 06: Start page of the screencast "Visioning and Comparison of Projects with SIMATIC Version Trail and SIMATIC Version Cross Manager"

    Download

    Screencast

    Download

    Visioning and Comparison of Projects with SIMATIC Version Trail and SIMATIC Version Cross Manager (English)
    (approx. 6.0 MB, 9 minutes runtime)
    Versioning_and_project_comparison_V52_e.zip ( 5996 KB )

    Screencast: Integrated Configuration with Catalog CA01 and STEP 7


    Figure 07: Start page of the screencast "Integrated Configuration with Catalog CA01 and STEP 7"

    Download

    Screencast

    Download

    Integrated Configuration with Catalog CA01 and STEP 7 (English)
    (approx. 10.5 MB, 9 minutes runtime)
    Catalog_CA01_STEP7_Import_V52_e.zip ( 10373 KB )

    Screencast: Functions of the Automation License Manager


    Figure 08: Start page of the screencast "Functions of the Automation License Manager"

    Download

    Screencast

    Download

    Functions of the Automation License Manager (English)
    (approx. 8.4 MB, 8 minutes runtime)
    License_Manager_V52_e.zip ( 8242 KB )

    Screencast: Premium Studio Installation


    Figure 09: Start page of the screencast "Premium Studio Installation"

    Download

    Screencast

    Download

    Premium Studio Installation (English)
    (approx. 8.9 MB, 4 minutes runtime)
    Premium_Studio_Installation_V52_e.zip ( 8835 KB )

    History

    Issue

    Modifications

    12/2008 First issue

    Additional Information
    Further graphically animated demonstration systems on the SIMATIC Software Engineering Suite are available in the following entries of the Application & Tools Portals.

    Title

    Link

    Basic languages languages LAD, FBD, STL 21062590
    High-level language S7-SCL 21062480
    Graphic language S7-GRAPH 21062148
    Testing and commissioning functions 21064135
    Communication with SIMATIC S7 21043576
    Visualisation - HMI Integration 21063246
    SIMATIC Manager 21064133
    S7 Architecture 21064245

    Filter criteria:
    Hardware platform: PC-based Automation, SIMATIC S7-300/S7-400
    Software: S7-GRAPH, STEP 7
    Entry contents: Demonstration systems

    Energy Saver systems for Induction motors.

    Written by Kang Abu on 6:20 PM

    Are they a sham? Do they work?

    There seems to be a resurgence in interest in the Nola energy saving algorithm for induction motors, with a number of manufacturers beginning to market "new" and "improved" versions of this technology.

    The technology was originally proposed and developed by Frank Nola of NASA in the mid to late 70s as a means of reducing energy wastage on small single phase induction motors. From the initial NASA developments, we saw a number of manufacturers world wide gaining manufacturing rights and marketing the technology in various forms. Difficulties were experienced in the early days in applying this technology to three phase motors in a fashion that it would perform with stability and reliability. Many patent applications were made in the early 80s covering variations on the technology as it could be applied to the three phase applications. An early application by Rutherford and Empson was successful in both operating as specified and in being granted letters patent. Many of the other early three phase patent applications were purely speculative and could not possibly achieve the desired results.

    The concept of energy saving has always been an attention grabber, especially when the promised savings are high and the potential for a reduction in running costs appears high. The initial introduction of this technology was a marketing person's dream, and some very extensive marketing plans were implemented in the early 80's. Unfortunately, the marketing was based on the results achieved with very small machines, and expectations were high because of the results so achieved. There were many promises made to prospective users based on extrapolated data which was not field verified at an early stage, and could not be realized in real applications. I recently reviewed some promotional material which disturbed me in that exactly the same misrepresentation as was common from some suppliers of the technology in the early 80's was again the foundation for a major promotion of this concept. As we experienced in the early eighties when we were manufacturing similar products, there appear to be many misconceptions about the performance of induction motors and many claims are based on the presumption that the induction motor at less than full load, is an inherently inefficient device. We withdrew from promoting this type of device as a result of expectations in the market place that resulted from over zealous marketing with totally unrealistic claims which could not be achieved without inventing perpetual motion. - I recall a refrigeration engineer who had been promised a 50% energy saving on his 50KW refrigeration units which were constantly running at about 50% load. He had tried numerous units to no avail, and eventually approached me on a recommendation. I asked him for the efficiency of the motors at this load and he found that it was about 87%. As he immediately began to see, there was no way that he could save 50% of the energy consumed by the motor. To do so would require a motor efficiency of over 100% which is just not possible with an induction motor and today's technology. There is no doubt that under the right conditions, the technology as proposed by Frank Nola and the many variants thereof, can reduce the energy drawn by an induction motor, and thereby achieve some benefit. The problem is that as the result of limited technical understanding of the induction motor and it's characteristics, erroneous claims are being made by extrapolation of results achieved with small motors. Worked examples often show flawed methodology in making power measurements in three phase three wire installations.

    1. The Technology.

    The basic algorithm is proposed by Frank Nola 20 years ago is to monitor the power factor of the motor, and to reduce the voltage when the power factor is dropping in a manner as to increase the power factor. There is a correlation between the power factor of the motor, and the motor efficiency such that the power factor will begin to fall when the efficiency of the motor falls. As such, the energy saving algorithm will act to improve the motor efficiency by reducing the iron loss in the motor. In some cases of very lightly loaded motors, it will also reduce the magnetizing current and where this is much greater than the work current, the copper loss may also be reduced. Although there may be some slight differences in the way the modern algorithm is implemented, I do not believe that there can be any significant improvement in the energy savings experienced in the early days when we were experimenting with this type of product. We found that the limitation was not the controller, but the inherent efficiency curves and characteristics of induction motors.

    2. Induction Motors

    Large induction motors are inherently very efficient with efficiency figures as high as 95% at full load being quoted. The efficiency will fall at reducing load, however the efficiency only falls by a small margin between full load and half load. For example, a Brook Crompton 110Kw motor type 7G-UD315S is rated at 92% efficient at full load, 91% efficient at three quarter load and 89% efficient at half load. As the shaft load is reduced, the current reduces, reaching a minimum of the magnetizing current of the motor. The magnetizing current for an induction motor can vary between 20% of the rated full load current and 60% of the rated full load current of the motor depending on the motor design. As the load is reduced, the power factor of the motor also reduces by a small margin. With the Brook Crompton 110Kw motor, the power factor at full load is quoted at 0.92, three quarter load is 0.91 and at half load is 0.88. In this example, the potential energy saving at half load is very small. It is probably not unreasonable to expect that the maximum efficiency of a given induction motor is not going to be much in excess of its rated full load efficiency, so a half load efficiency gain of 4% may be achievable under ideal conditions, but with the non sinusoidal currents created by the use of an energy saver, this is not achievable in practice.

    Toshiba 90kw efficiency curves

    Induction motors have five major components of loss; Iron loss, Copper loss, Frictional loss, Windage loss and Sound loss. All these losses add up to the total loss of the induction motor. Frictional loss, windage loss and sound loss are constant, independent of shaft load, and are typically very small. The major losses are Iron loss and Copper Loss. The iron loss is essentially constant, independent of shaft load, while the copper loss is an I2R loss which is shaft load dependent. The iron loss is voltage dependent and so will reduce with reducing voltage. For a motor with a 90% full load efficiency, the copper loss and iron loss are of the same order of magnitude, with the iron loss typically amounting to 25 - 40% of the total losses in the motor at full load. If we consider for example, an induction motor with a full load efficiency of 90%, then we could expect that the iron loss is between 2.5% and 4% of the motor rating. If by reducing the voltage, we are able to halve the iron loss, then this would equate to an iron loss saving of 1-2% of the rated motor load. If the motor was operating under open shaft condition, then the power consumed is primarily iron loss and we could expect to achieve a saving of 30% - 60% of the energy consumed under open shaft conditions. It must be reiterated however, that this is only about 1-2% of the rated motor load. For example, if we take a Toshiba 2 pole 22kW D180M motor, we find a full load efficiency of 90.9%. This motor has a rated iron loss of about 25% of the total loss. This amounts to 22 x .091 x .25 = about 500 watts. At best, I would expect to halve this loss, resulting in a saving of 250 watts at light load. Under open shaft conditions, this may well amount to 30% of the energy consumed by the motor, but it is still only about 1% of the motor rating. If the energy wasted by the motor is small, then there is very little to be saved, irrespective of the technology used

    Motor Current components

    The current flowing into an induction motor comprises three major components, magnetizing current, loss current and load current. The magnetizing current is essentially constant, being dependent only on the applied voltage. The magnetizing current is at phase quadrature to the supply voltage and so does not contribute to any Kw loading except for the contribution to the copper loss of the motor. The magnetizing current causes a reduction in the powerfactor seen by the supply. The loss current is essentially a Kw loading as is the load current. For a given shaft load, the output Kw must remain constant. As the terminal voltage of the motor is reduced, the work current component must increase in order to maintain the shaft output power. (P = I x V) The increasing current resulting from reducing voltage can in many instances result in an increasing I2R which is in excess of any iron loss reduction that may be achieved. For a large motor, the magnetizing current can be as low as 20% of the rated full load current of the motor. Three phase induction motors have a high efficiency to less than 50% load, and experience suggests that there is no realizable saving to be made until the motor is operating at well below maximum efficiency. (typically below 25% load) A Toshiba 150KW 4 pole machine exhibits a full load efficiency of 94.6%, 75% load efficiency of 94.8%, 50% load efficiency of 94% and a 25% load efficiency of 90.3%. There are many examples such as this which illustrate that the induction motor is efficient at considerably less than full load, and as such there can be very little advantage in using an energy saving algorithm on anything other than a small inefficient motor. Using SCRs to reduce the voltage applied to an induction motor operating at reduced load and a high efficiency will reduce the iron loss, but there will be an increase in current to provide the work output. This increase in current will increase copper loss by the current squared, offsetting and often exceeding the reduction in iron loss. This will often result in an increase in the total losses of the motor. i.e. will have the reverse effect to that for which it was installed. The potential to save energy with a solid state energy saving device, only becomes a reality when the motor efficiency has fallen. This generally requires a considerable fall in power factor, typically down to below 0.4 under full voltage operating conditions. Large motors have a very low iron loss, (often 2 - 6% of the motor rating) and so the maximum achievable savings are small relative to the motor rating.

     KW 0.37 0.75 2.2 5.5 11 30 110 355
    eff 66.2 74 82.5 86.4 89.2 91.6 93.2 94.9
    pf 0.69 0.83 0.84 0.85 0.86 0.88 0.91 0.88

     

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    Very small motors, (particularly single phase motors) have a much lower efficiency, and a much higher iron loss and so the potential to save energy is considerably higher.

    KW  0.25 0.37 0.55 0.75 1.1 1.5 2.2
    eff 63 68 69 70 72 76 78
    pf 0.6 0.63 0.66 0.7 0.74 0.84 0.86

    3. Measurement techniques

    To establish the energy saved in a given installation, it is important to ensure that the measurement techniques are appropriate and correct. Three phase Induction motors are a three wire circuit with a power factor which can vary between 0.1 and 0.95. Three phase power measurement techniques must be employed in order to achieve meaningful results. The standard methods of measuring the input power on a three phase three wire circuit, are either to use the single phase watt meters, one per phase and sum the results, or use the two watt meter method, or a three phase watt meter. Measurements made on one phase, and multiplied by three can be extremely erroneous, especially under light load conditions. The Kilowatt loading on the three phases at light loads can be severely unbalanced even though the currents may not be unbalanced to the same degree. When using the two watt meter method, care with phasing is very important as this can totally alter the results. Measurements made by multiplying voltage, current and powerfactor on each phase can work with a continuous sinusoidal current provided that each phase is individually measured, and the power consumption from each phase is then summed to give the three phase power consumption. Measurements on non sinusoidal currents and or voltage must be made with true integrating watt meters. The formula of P = V x I x pf applies only with a continuous sine wave current and voltage. The introduction of SCR or triac switching elements into the circuit to control the voltage results in non sinusoidal current and voltage, and under these conditions current, voltage and power factor measurements are meaningless in determining the power consumed. By definition, power is the integral of instantaneous volts x amps of the period of one or more cycles. At the instance that current is flowing, the SCR or triac is turned ON resulting in full line voltage at that instance in time. Therefore, there is no difference between measurements made on the input of the energy saver or the output of the energy saver with the exception that there is some loss in the energy saver which will appear on input measurements but not output measurements. There is no way that the power consumed by the motor can be measured or approximated by measurement of the current in one phase, the power factor, and the output voltage applied to the motor, all multiplied together. This results in totally fictitious results. Comparisons are best made under controlled conditions with a true Kw or kWh metering system. The rotating disk kWh meter is what the power bill is based on and so it is a good instrument to use.

    4. Claims

    A recent review of yet another newcomer on to the international market with an energy saving device for induction motors showed the same inaccuracies and misrepresentations that were common when the technology was first promoted. The information given displays a number of inaccuracies which severely compromise the credibility of the claims that are made. The statement is made that: "induction motors draw the same current whether loaded or unloaded, the efficiency goes down when less than the rated load is applied to the motor." This statement is demonstrably incorrect and is the foundation of the basic assumption that motors operating at half load will save up to 50% percent power consumed. This statement was contradicted in the same literature by the statement that: "the current at half load was about 75% of the full load current." This statement would be true on a small single phase motor with a magnetizing current in the order of 50% of the rated full load current, or higher. Another statement that, "the company believes that it was the first to develop and introduce an energy savings device utilizing digital technology." The company is somewhat ill informed as companies such as Fairford had a micro based energy savers available more than 16 years ago. Rockwell have had one available for a number of years also. Many of the test results, quote irregular results such as induction motors with power factors as high as 0.99 and power factors that drop as the voltage is reduced, when in fact the algorithm works by reducing the voltage to maximize the power factor. One report shows a "voltage saving of 10.7% and a "current saving of 13.0%" resulting in a "KVA saving of 23.7%". This is absurd and suggests that other figures are also incorrect. In reality, the current only flows through the triac while it is turned on, so the current must be multiplied by line voltage to give the correct results. This can be verified by the use of true power board type metering. The true saving is more like 13% KVA. A detailed look at the quoted examples of energy saving is quite alarming, as the quoted results are obviously not correct. In one such quoted example, the application was for a Chilled water pump 75Hp, 95 Amp, 440V 3ph. Tests were quoted as below:

    Without Energy saving device

    volt  479
    amp 68
    kw 32
    kva 33
    pf 1.0

    Immediately there are some anomalies here:
    a) A three phase motor drawing 68 amps at a line voltage of 479 volts would be drawing P = V x A x pf x Å3 = 479 x 68 x 1 x 1.732 = 56KW Where did the 32 KW come from?? 32 = 479 x 68 x 0.98. (line voltage times current times powerfactor)
    b) The KVA drawn by a three phase load is equal to V x A x Å3 . in this case, the KVA demand would be 479 x 68 x 1.732 = 56KVA, not 33 KVA as quoted.
    c) Induction motors never have a power factor of 1.0 Even very large and very efficient motors do not very often exceed 0.95 power factor.

    With Energy Saving Device

    volt 460
    amp 68.8
    kw 31
    kva 32
    pf 0.99

    a) The power can not be calculated but would probably be as high as without the energy saving device, in fact it would probably be higher due to the losses with in the energy saver and the increase in i2R losses in the motor. The power quoted in this example appears to have been calculated on the basis of output current times output voltage times pf. (460 x 68.8 x 0.99 = 31.1KW) If we were to accept this calculation, then the power into the energy saver must be line volts times line current times pf, = 479.9 x 68.8 x 0.99 = 32.7KW. This would be what the consumer was paying for as the supply metering is on the input side of the energy saver, and the net result is that the consumer is paying for more!! If we continue on the assumption that the measurements and calculations are in fact valid, then the energy saver is dissipating 32.7KW - 31.1KW = 1.6KW and will there fore be operating at a very high temperature. I expect that if measurements were made in this installation, there would in fact be a net loss rather than a gain in overall efficiency.
    b) Likewise, the KVA will be a little higher than before, 479 x 68.8 x 1.732 = 57KVA. c) The energy saver should work to improve the power factor, not reduce it. If the power factor reduced, the energy saving device, (provided it was working correctly) would reduce the voltage further until the power factor rose again. These results have definitely not been made with the correct instrumentation, or the instrumentation has not been used / interpreted correctly. It is obvious that some of these figures are not measured results, but would appear to be incorrectly calculated. I suspect that perhaps the voltage and current readings could be true representations of the installation, but the KW, KVA and pf with and without the energy saver can not be correct. A second quoted example is for a 10 ton roof top air conditioner. Tests quoted were:

    Without Energy Saving Device

    volt  485
    amp 31.2
    kw 24.8
    pf 0.95

    The quoted kw would appear correct based on the quoted voltage, current and power factor.

    With Energy Saving device

    volt  430
    amp 26.4
    kw 17.8
    pf 0.91

    a. The quoted power is equal to the calculated value based on a calculation using the reduced output voltage. This could not be a measured value, as a measured value would certainly not reduce by this amount. As described earlier, the metering is not affected by the reduced output voltage. b. The quoted power factor has dropped from 0.95 to 0.91. This is contrary to the basic operation of the device. The power factor should improve when the energy saver is used. c. With a power factor of 0.95 initially, there would not be a drop in current with a falling voltage. As the majority of the KW load is shaft load, a drop in voltage will result in an increase in supply current. If we assumed that in this case we were using an inefficient motor at say 80% efficiency, then we would have a shaft load of 24.80 x 0.80 = 19.84 kw. The shaft load portion of the current at 485 volts would be 23.617 amps per phase. If the voltage was now reduced to the quoted 430 volts, then the shaft load KW remains constant and the shaft load current would rise to 19.84 / 430 / Å3 = 26.6 amps which is slightly above the quoted current at the reduced voltage. As there would still be magnetizing current , copper loss current and iron loss current, it would appear that these figures are also fictitious. These are only a couple of randomly selected examples. There are many more quoted by this one supplier showing similar anomalies. Another supplier quotes "in typical applications, levels of utilization are approximately 50% with power wastage estimated to be between 40% and 80% of the motor full load rating". - " Unfortunately, motors have no way of intelligently adjusting the amount of electricity they draw in relation to the work they do." The implication is that the motor is inherently very inefficient at less than full load, but this is not what the motor manufacturers show in their data sheets. This supplier also "delivers a speedy payback - normally less than two years,... " .???

    5. Pay Back Periods

    NB The costs quoted here are based on New Zealand prices in the eary 90s. Prices and costs have changed, and differ in different countries. You need to apply your costs, but the theory still applies.
    Increasing energy costs and reducing technology costs can dramatically improve payback periods, but increasing motor efficiencies pushes them out. You need to do your tests and your sums in your market based on your test results and local costs.

    In the right applications, with the right motors, there will be some energy saved. In many such situations, the energy saved would be increased by altering the operation of the machine to spend less time idling. To calculate the payback period, it is essential to have an accurate measurement of the actual energy (KW) being saved. When the energy saved is known and verified, then this can be multiplied by the cost of the energy per kilowatt hour to give a cost saving per hour. Dividing the savings per kilowatt hour into the installed cost of the energy saver, will give the required number of operating hours to give a payback. For example, a small punch press operated by a 1.1 KW motor, could save as much as 300 Watts per hour, depending on the design of the fitted motor. If the cost of energy is 14 cents per KWH, then at a 40 hour week operation this would amount to a cost saving of $1.68 per week. To achieve a pay back period of two years, this would require a maximum installed cost of $168.00 Prices quoted recently by one supplier would put the cost of the unit at $3,633.83, or a payback period of 43.2 years!! or a return on investment of 2.3 percent per annum! With a larger motor, perhaps 22 KW operating a granulator which runs continuously, and spends 90% of its time unloaded, the potential savings could be as much as 1.1 KW per hour during the off load period, amounting to 40 x 1.1 x 0.9 = 39.6 KWH per week. At 14 cents per kWh, this would amount to a savings of $5.54 per week. To achieve a payback of two years, this would require a maximum installed cost of $554.40. A quoted price of $4919.07 would yield a payback period of 17.7 years, or a return on investment of 5.6%.. A greater saving would be made by switching the machine off and only operating it on demand. Turning the machine OFF during it's off load time could save 2.5KW per hour which amounts to a saving of $12.60 per week, or $630 per year. which is much higher than that achieved by using an energy saver. In many industrial environments, the cost per KWH would be less than the 14 cents used in the equations, and therefore payback periods would be greater, or installed costs must be less than the examples above. If we take a typical 75 Kw 2 pole motor, and operate it in it's most inefficient state, (open shaft) then we could achieve a 1.5 KW saving. at 14 cents per KWh, this would amount to a saving of $420 per year if the motor runs for 40 hours per week. To achieve a pay back of two years in this situation, the installed cost of the energy saver would need to be less than $840. In reality, with loads of this size connected, the energy cost would be lower, and the machine would not spend 100% time at idle, so the energy saved would be less and the pay back period would be much longer. The cost of a unit to operate on a motor of this size would be a lot more expensive than this also. In this case using the figures quoted, the payback period would be 25.9 years.

    Conclusions

    There is no doubt that the basic technology of reducing the voltage on a motor which is operating at less than maximum efficiency, can result in a reduction of the iron loss of the motor. In a case where the motor has a very high magnetizing current, and it is operating at essentially open shaft conditions, there can be a reduction in copper loss also. In practice, with a partially loaded motor, a reduction in the voltage applied to the motor will reduce the iron loss, but the corresponding increase in the load current can cause an increase in copper loss that is greater than the reduction in the iron loss, resulting in a net increase in motor losses. -Worthwhile power savings are only achievable where the iron loss is an appreciable portion of the total power consumed by the motor, and where the amount of the iron loss is significant relative to the motor rating. This technology only achieves useful results on small, inefficient and predominantly single phase motors. Unfortunately, once again we have examples where a lack of knowledge about basic motor characteristics and a poor understanding of power metering on three phase systems have resulted in extrapolations and estimations which totally misrepresent the achievable results from the application of this technology. Only energy that is being wasted, can be saved. Large motors do have a much higher efficiency than small motors, and this basic fact seems to be missed in creating examples of potential energy savings. Proper tests would demonstrate that energy savings per kw motor rating are much higher for small motors than large, and the potential market for this technology is really confined to the small single phase applications. I can find no evidence of a technological advancement which can result in increased energy savings over and above the energy wasted by the motor. According to current laws of physics, this would be considered an impossibility. Worked examples based on energy costs, motor losses and quoted energy saver pricing yield payback periods in the 10 to 40 year range, nowhere near the quoted figures of less than two years! In many cases, the return on investment is well below standard bank interest rates. To borrow the money to purchase the equipment would be a loss situation. Putting the cash into a savings account would be a higher yielding investment than the purchase of some of these energy saving devices. In summary, I would like to note the following points: The basic concept of reducing the voltage on induction motors operating at less than full load, and thereby reducing the energy consumed, works provided that several constraints are applied:

    a. The motor efficiency can only be improved when it has dropped considerably below the maximum efficiency for that motor.
    b. As the maximum energy that can be saved is a portion of the iron loss, the best savings are going to be on motors with a very high iron loss. Typically, these will be small motors, operating above their design voltage, or below their design frequency.
    c. Where payback periods are a consideration, the savings need to be related, not to the power consumed while the unit is running, but to the power saved relative to the cost of the unit, which is dependent on the motor rating.
    d. Tests need to be carried out using rotating disk kWh meters, and care must be taken that the operating conditions are the same with and without the energy saver connected. Tests under open shaft conditions, yield a high percentage saving, but the actual savings in kWh is indicative of the maximum dollar saving that can be achieved with that motor. As the load increases, the kWh savings will reduce as will the percentage energy savings.
    e. In many situations where energy savings can be made, greater energy savings can be achieved by either altering the operation of the machine to minimize the time operating at idle, or replacing the motor with a more efficient motor. This can yield an improved payback period relative to the use of an energy saving device.
    f. Partially loaded motors fitted with energy saving devices can dissipate more energy than without the energy saving device.
    g. Experience gained with this type of technology indicated that there was no significant improvement to be made on motors operating with a power factor greater than 0.4.
    h. Experience has shown that the best results are on small single phase motors operating continuously, and predominantly under no load conditions. Small motors operating at a voltage well above their design voltage (i.e. 440Volt motor operating on 485Volt) will exhibit a much higher iron loss and therefore achieve much increased savings.
    i. Real payback periods of less than two years are rare, requiring a very good application, a very lossy motor and a very cheap energy saver.

    PID Control Systems.

    Written by Kang Abu on 6:13 PM

    PID is an enhanced feed back system designed to determine the overall system behaviour. A simple feedback system comprises a single feedback path and is proportional only.

    PID Control System

    Feedback systems are used to reduce or eliminates errors. In a typical PID installation, we have a set point and the PID feedback systems works to keep the output value equal to the setpoint value. It is possible for the setpoint value to be a changing value, but this can add complication.
    An ideal system would have a linear transfer function, zero phase shift and zero delay. Under these conditions, a proportional control is all that is needed.
    A real world system commonly has a non linear transfer function (pumping is a classic case) and there can be a considerable delay between the "action" and the "reaction" (measured value). If a purely proportional control is applied under these conditions, there will be overshoot and oscillations and it will not be possible to achieve a stable output over the whole control range.

    One way to see the effect of system delay between the input and the output of a system, is to apply a step function. If the response is perfect and there is no dely, the output will accurately track the input with a proportional feedback system..

    If there is a delay, then the error signal fed back is the result of an input some time earlier. By the time the controller sees the output at the correct level, it has already increased the drive too much. The net result is that there is an overshoot, followed by an undershoot and effectively a decaying oscillation.

    PID Response curves
    The addition of the proportional feedback reduces the risetime seen on the output, but adds over and undershoot and a decaying oscillation. The output is closer to the required output, so the error is reduced.

    The PID controller is a three term controller incorporating a Proportional feedback element (P), an Integral feedback Element (I) and a Derivative feedback element (D).

    The Integral element is added to the proportional element to provide a means for eliminating a changing offset in a non linear system, and to slow down the reaction to allow for the time delays in the system. This will reduce the overshoot experienced in the practical proportional control system.

    The derivative element is added to provide a means of reducing sudden changes in the output and will provide a faster response to step functions and transients.

    Setting up a PID system is a balancing act with all terms interacting. Excessive Integral gain will slow the response rate excessively and may result in the output moving with load changes. Insufficient integral gain will cause the output to overshoot and oscillate around the set point. Excessive derivative gain will result in instability with severe oscillation around the set point. The derivative gain should be used sparingly to improve transient performance, and is best added in only after the proportional and integral gains have been set for best performance. The derivative gain can then be slowly increased to the point of best stability of the output.

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