Damping is a smoothing function to make process measurement with point-to-point variability a stable measurement that reflects the moving average or the product measurement for adjustment and control.
If you are measuring hog fuel for a boiler or ore for mining or even paper moisture for label stock, you want the measurement quickly and also representative of what is being measured over time so that the control scheme doesn’t “chase itself” and instead optimizes operation. Instead of reacting to point-to-point measurement variation that causes over compensation, a moving average allows control based on a more representative continuous measured value.
The moving average “smoothes” the measurement to allow for real time process control of application dependent unit operations. Damping is the expression of the “Time Constant”. The Time Constant is the time it takes for 2/3 of a step change to be reflected in the measured value. The Time Constant or Damping is necessary to make the measurements more useful to optimize process control.
Example: System is operating at 2%, an upset causes the constituent (moisture, organic, active ingredient or other) to 8%. The system upset is 6% in this example. The damping time constant is the time for the digital display an analog output to reflect 2/3rds of this change. If the time constant is set for 1 second, the display and outputs will display 6% at one second. If the trend continues, it will continue to increase value. If trend stops or “lines out” (stabilizes), it will also reflect that in the moving average.
The damping is used from 1 to 10 seconds depending on application to smooth the real time measurement into a useful process control measurement. There are also other integration and average measurements available.
Another question might be “Can you afford not to have a cross direction coat weight or moisture measurement?”
Process Sensors Guardian Nova Series of Cross Direction Web Profile Systems are designed to encourage early entry into the measurement and control of the web profile.
Our PC based Guardian Cross Direction Web Profile System is the work horse of the industry. Fast, accurate, reliable, Ethernet communications, analog outputs, remote on-line diagnostics and Easy-to-Operate, the Guardian is an established brand in the industry.
What if you’re a new or expanding company that doesn’t have a lot of capital? You get a new or bigger contract re-newel. Normal procedure requires start up, samples sent to lab, 20 minute response at best, make adjustments, new lab sample for confirmation and operation at best. Contract is great but the time to get to set point is more critical and impacts production volume. Also, if there’s a wedge or edge splurge that messes up profile, it messes up roll delivered to customer. A complete cross direction web profile system pays for itself quickly.
Guardian opportunities now include a simple scanner, transmitter and digital display. The basic system does not include a cross direction web profile. It provides a digital measurement of coat weight or moisture across the web. It can be programmed for automatic scanning or to machine direction lane with trend plot. If you spot a problem, you can locate it, adjust the nip pressure, dye bolt, skew, or whatever is needed and immediately see the result to obtain a uniform profile. This is especially important on start up. It allows emerging or budget restricted companies a quick way to provide their production operators a tool for process control.
Measuring moisture or coat weight, film thickness or PSA Cross Direction Web Profile speeds start up, reduces out-of-spec product and increases profits.
The Guardian 12” Operator Interface System offers the same features as the basic system with a complete Cross Direction Web Profile. No data logging, but it offers a quick, accurate and easy-to-operate system to optimize start up and detect problems. Ideal for lowering start up time and increasing production for emerging companies.
PC Based System can communicate with an HMI (Human Machine Interface) meaning that the operator can simply change a roll or customer order via the HMI and that activates appropriate product and historical codes automatically. Multiple scanners, transmitters and measurements such as coat weight and residual moisture!
Fair enough question.
The answer can be expressed in a couple of ways depending on your background and interest.
Moisture, oil/fat and coat weight etc., are all components measured with established Near Infrared (NIR) Technology. Moisture is measured at 1.94µ or 1.42µ. Organic coatings are measured at 2.34µ and oils/fats at 1.72µ. These are well established applications in theory, practice and documented literature.
The accuracy of a NIR transmitter is dependent upon calibration samples across a realistic dynamic range. Normally 3 to 5 samples throughout the dynamic range and including the set point target are the best approach for calibration. Near Infrared absorbance and constituent content (lab value) enjoy a linear relationship. The transmitter must be most accurate at the set point.
The zero and span calibration controls are used to make the Near Infrared transmitter display values match the lab values within the limitations of laboratory accuracy and sample handling. Collecting lab vs. NIR Transmitter values allows for a linear regression to be performed that will yield a correlation co-efficient, standard error, slope and y-intercept.
Our “Zero” is an offset adjustment, meaning that if the measured value is 2% up or down, that it just needs an offset or zero adjustment around the set point. The “Span” is a sensitivity adjustment, meaning that for a given change in absorbance, there is a given response in the digital measurement. The fully automatic calibration sequence adjusts the zero and span for the operator based on these calculations to provide the correct Zero and Span for the analyzer to accurately measure and display the NIR measurement.
Enter Calibration Parameters of Lab vs. MCT Transmitter
Correlation Co-efficient, Standard Error and New Zero and Span
Large 5.7” Display with Analog Outputs & Ethernet Communications
Cross Direction Web Profiles
We are all aware of the Shale Oil and Natural Gas Boom that’s lowering the price of gas at the pump. Did you know that there is a Wood Pellet Boom going on too?
Maybe not, and that might be because it’s happening in the US Southeast and shipping to Europe!
Europe’s move towards cleaner fuels is driven by tax and other incentives that make wood pellets a very attractive fuel for heating and boilers. The wood pellets are highly energy efficient and are generally made up of what would traditionally be waste wood, and they’re from a renewable energy resource.
Enviva has opened five pellet mills in less than five years to increase supply. Over three of the UK’s largest power plants have converted from coal to wood pellets as a fuel source which increases demand. Enviva has long employed moisture transmitters to optimize pelletizing and insure highly efficient pellets that don’t crumble. Process Sensors MCT460-WP moisture transmitter features a large digital display, analog outputs and Ethernet communications.
The demand for wood pellets is growing rapidly across Europe with almost 50% of exports to the UK. Moisture is important for the energy efficiency, pellet density and ability to maintain structural integrity (not crumble or stick together). Click Here to learn more about the importance of moisture measurement and control in the Biomass industry.
Pack Expo was a great show with Eduardo Villasenor and Luis Rivera of J.A Diaz, our Mexican Distributor, and ThermoCense, our Chicago area representatives joining us. We visited with many existing customers with new projects and new customers. Great Show for us!
Highlight Sunday night was Nick Wallenda’s tight rope walk a few blocks from the convention center. Happy Friday from Process Sensors!
Halloween is thought to be an outgrowth of the Celtic holiday for “Summer’s End” celebrating the end of the Harvest Season. The ancient pagan festival began over 2,000 years ago and many Celts believed that the dead walked among the living during this festival. The idea of dressing up as the dead in costumes may have been to fool the spirits that the living were one of them and thus pass them by. Today it’s a huge American Commercial Holiday that accounts for billions of dollars in sales and continues to grow worldwide.
Happy Halloween from Process Sensors…and Annabelle!
Speeding up the start-up process, reducing scrap and rejected material, archiving data against claims and improving QC/QA are among the many benefits of measuring your hot melt thickness web profile with a NIR Transmitter and Guardian Scanning Profile System.
Whether you operate doctor blades, die bolts or other hot melt applicators, a uniform web profile is important to you and your customers. Often times the system is started up and stopped while a sample is sent to the lab for analysis. After receiving the results, the applicator is adjusted and started up only to be stopped for another sample and analysis to confirm correction. Sometimes the adjustment over compensates and the process repeats itself. With a web profiler, the machine can be adjusted while running and the results immediately seen on the hot melt profile display. A trend chart and plot below illustrates the hot melt process in adjusting the applicator to meet a 1.4 mils target set point. Red is alarm out of specification, yellow is alert getting out of specification and green is good at a set point of 1.4 +/- 0.1 mils hot melt thickness.
Hot Melt Measurements are typically measured with Near Infrared (NIR) transmitters that provide a digital display in engineering units, analog outputs and a digital interface. The NIR non-contacting Hot Melt measurement is extremely accurate and stable with no regulatory requirements. The measurement can be fixed point or scan across the web to provide a cross direction web profile.
The Guardian Web Profile System provides a Cross Direction profile on a large flat panel LCD in an economical and attractive enclosure. The Guardian is fully automated with product recipes for scan speed, zone average, and data logging digital outputs. This is a complete system with automatic web edge detection to provide the highest value performance to cost ratio. The system can supply CD Web Profiles and MD Trends for hot melt thickness, residual moisture and temperature. Multiple measurements can be displayed on a single large display screen.
The Entry Level Profile System provides a simple and inexpensive automatic scanning frame with a 12” Operator Inteface (OI) for profile display and controls mounted on the frame end. The Simple Cross Direction Scanning System with Digital Display allows for automatic scanning or jogging to fixed position for machine direction measurement and display on a 5.7” touch screen.
Guardian Scanning Frame System : Process Sensors Corp. announces a new economical introductory level Guardian CD Web Profile System for the Packaging, Tape and Label Markets. The New Guardian OI based system features a single frame with 12” Touch Screen Profile Display. The Guardian System can measure moisture, water based coat weight, film thickness and organic deposition on a wide variety of substrates including paper, film, foil, metal, non-wovens and more.
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