Instrumental measuring system

Tools (new instrumentation measurement systems and platforms materials and processes for alternative, nonfossil fuels)... 

The top-loading scalepan TMAs require no calibration. Instruments fitted with the voice coil type motors will require calibration. Most instruments achieve this by applying one or more known masses (which can be accurately measured on a balance cahbrated by traceable standards) and nulling the displacement that occurs. This way the force required to rebalance the applied mass is obtained independently from the displacement measurement. The instrument measuring system will adjust the voltage or current applied to the coil, and when the displacement has been successfully nulled this value is equivalent to the force due to the applied mass. The value of force to current should be linear over the range of operation of the instrument. 

In order to be able to reduce prices, even more and more test- and measurement systems are integrated on PC-boards. The powerful and inexpensive PC eomponents can be directly u.sed for these (virtual) instruments. The limited dimensions of the PC boards require a reduction to the absolute necessity of the electronic components. Analogue signal proeessing must carried out by software as far as possible. 

Finn, A.E., Instrumented Couplings The What, the Why, and the How of the Indikon Hot Alignment Measuring System, Proceedings of the 9tli Turbo-machinery Symposium, Texas A M University, pp. 135-136, 1980. 

An ICP-OES instrument consists of a sample introduction system, a plasma torch, a plasma power supply and impedance matcher, and an optical measurement system (Figure 1). The sample must be introduced into the plasma in a form that can be effectively vaporized and atomized (small droplets of solution, small particles of solid or vapor). The plasma torch confines the plasma to a diameter of about 18 mm. Atoms and ions produced in the plasma are excited and emit light. The intensity of light emitted at wavelengths characteristic of the particular elements of interest is measured and related to the concentration of each element via calibration curves. 

Because of these solutions, important technical data can be transferred from local instrumentation (control system) through data-based controllers to a control station with computers. The operator may use the many variations that the software data system provides. Technical data operation may be digital off/on messages such as the status of operation and the performance of alarms or analog measurements such as temperature, humidity, pressure, velocity, energy usage, etc. 

The time constant is one way of determining the dynamic features of a measurement system. Not all instrument manufacturers use the time constant some use the response time instead. The response time is the time between a step change of the measured quantity and the instant when the instrument s response does not differ from its final value by more than a specified amount.The response time is defined according to a deviation from the final value. Often response times for the relative deviation of 1%, 5%, 10%, or 37% are used. The corresponding response times are denoted by 99%, 95%, 90%, or 63% response time, respectively. The response time for a first-order system can be solved from Eq. (12.15). Note that the 63% response time of a first-order system is the same as the time constant r of the system. 

A measurement system consists of the operations (i.e. the measurement tasks and the environment in which they are carried out), procedures (i.e. how the tasks are performed), devices (i.e. gages, instruments, software, etc. used to make the measurements), and the personnel used to assign a quantity to the characteristics being measured. 

Fig. 24—Measuring instrument (a) interference lights of the measuring system (b) the scheme of the experiment system. For applying an external voltage to the oil film, one end of direct current (dc) power keeps contacting with the Cr layer on the glass disk, and the other end contacts a shaft welded on the steel ball through an electric brush. The SI02 layer with a thickness of 300 nm has been coated on the surface of the Cr film.

Instrument measurement response can often be important in the overall system response. The thermal response of a simple thermometer bulb, immersed in fluid, as shown in Fig. 2.6, is the result of a simple heat balance in which... 

Over the years, many instruments have been developed for and used in the scientific laboratory. Today, the computer is used as a major tool in the scientific laboratory for the capture, manipulation, transfer, and storage of data. Consequently, the concern for data quality has shifted from the instruments that are used in the generation of the data to these electronic systems, often neglecting the fact that the data are only as accurate as the instrument measurements. For instance, many electronic systems can be used in chromatography analysis, from the electronic log book where the test substance inventory is kept, throughout data capture in the instrument, to the digitized electronic signal that is the raw data on the computer network. For crop residue samples, the... 

Therefore, signal functions y(z) always represent a convolution of the true signal function y z)trUe and the characteristic function of the analytical instrument h(z) which characterizes all the insufficiencies of the measuring system ... 

Precision of a measuring system and with it also of signals and signal functions obtained by instrumental analytical methods, is characterized by the signal-to-noise ratio. 

The instrument for measurement of radon with weather parameters and water use was designed, calibrated and used in the field for 1.5 years with excellent results. The power surge and power interruptions were the only limitations on the use of the instrument. The system software was written mostly during the design phase of the project. However, modifications were made in the software to permit better data collection during power interruptions. Battery backup was needed to keep the data during interruptions of our one week studies. 

The basic components of the solid state spectrometer are the same as the solution-phase instrument data system, pulse programmer, observe and decoupler transmitters, magnetic system, and probes. In addition, high-power amplifiers are required for the two transmitters and a pneumatic spinning unit to achieve the necessary spin rates for MAS. Normally, the observe transmitter for 13C work requires broadband amplification of approximately 400 W of power for a 5.87-T, 250-MHz instrument. The amplifier should have triggering capabilities so that only the radiofrequency (rf) pulse is amplified. This will minimize noise contributions to the measured spectrum. So that the Hartmann-Hahn condition may be achieved, the decoupler amplifier must produce an rf signal at one-fourth the power level of the observe channel for carbon work. 

Brabender make a whole range of instruments for testing flour. These instruments are the standard ones in use in the UK, Germany and North America. The company has recently produced new versions of these instruments that use electronic measuring systems rather than the mechanical systems previously employed. The new models use the same name but with the suffix E. Thus, the new model Extensograph is the Extensograph-E. 

It is important that personnel understand how to achieve safe operation, but not at the exclusion of other important considerations, such as reliability, operability, and maintainability. The chemical industry has also found significant benefit to plant productivity and operability when SIS work processes are used to design and manage other instrumented protective systems (IPS), such as those mitigating potential economic and business losses. The CCPS book (2007) Guidelines for Safe and Reliable Instrumented Protective Systems discusses the activities and quality control measures necessary to achieve safe and reliable operation throughout the IPS lifecycle. 

The single beam instrument measures directly the amount of energy transmitted by the sample. They give the most accurate transmittance measurements and is particularly helpful for quantitative analysis. It has simpler and more reliable systems than double beam. 

SixSigma [On-line], Measurement System Capability Manual, Available http //www.6sigma.us/ MeasurementsystemsMSA/measurement-systems-analysis-MSA-p.html, accessed 1 April 2009 I. Verhappen, Typical process analyzer application justification, in Analytical Instrumentation-, Practical Guides for Measurement and Control, R.E. Sherman and L. Rhodes (eds). Instrument Society of America, Research Triangle Park, 1996. 

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