Readout device

Measurement Requirements. Any analysis of measurement requirements must begin with consideration of the particular accuracy, repeatabihty, and range needed. Depending on the appHcation, other measurement considerations might be the speed of system response and the pressure drop across the flow meter. For control appHcations repeatabihty may be the principal criterion conversely for critical measurements, the total installed system accuracy should be considered. This latter includes the accuracy of the flow meter and associated readout devices as well as the effects of piping, temperature, pressure, and fluid density. The accuracy of the system may also relate to the required measurement range. 

Making use of the information from monitoring probes, combined with the storage and analysis capabilities of portable computers and microprocessors, seems the best method for understanding corrosion processes. Commercial setups can be assembled from standard probes, cables, readout devices, and storage systems. When these are coupled with analysis by corrosion engineers, the system can lead to better a understanding of in-plant corrosion processes. 

The CCD MOSFET is a destructive readout device - there is only one measurement per charge packet. However, an infrared amplifier can be read ouf several times, with averaging and corresponding reduction in the effective readout noise (16 reads can reduce the noise by a factor of a/Tg or 4). In theory, multiple readout of an infrared amplifier could achieve extremely low noise, but in practice, due to other complications, the noise reduction usually reaches a limit of 4-5 improvement (achieved after 16-32 reads). 

Figure 2, Block diagram of a liquid chromatograph. A, solvent reservoir B, filter C, pump D, pulse dampener (optional) E, pre-column (used only in liquid-liquid chromatography) F, pressure gauge G, infector H, column I, detector J, fraction collector K, recorder or oth readout device.

The equipment used in gamma spectroscopy includes a detector, a pulse sorter (multichannel analyzer), and associated amplifiers and data readout devices. The detector is normally a sodium iodide (Nal) scintillation counter. Figure 27 shows a block diagram of a gamma spectrometer. 

In general, an instrument consists of four components a sensor that converts a property of the solution into a weak electrical signal, a signal processor that amplifies or scales the signal and converts it to a useable form, a readout device that displays the signal for the analyst to see, and a power supply to provide the power to run these three components. The information flow within the instrument occurs with the movement of electrons, or electrical current. 

The readout device is a translator like the sensor. It translates the electrical signal produced by the signal processor to something the analyst can understand. This can be a number on a digital display, the position of a needle on a meter, a computer monitor display, etc. The readout device is not specific to the measurement. It can take the signal from any signal processor and display it. 

The general principle of analysis with analytical instrumentation is depicted in Figure 6.4. Some property of the standards and sample solution is detected and measured by the instrument. An electronic signal is generated proportional to this property and read on a readout device. 

Sensor, signal processor, power supply, and readout device. 

Figure 3.24 — Typical system for piezoelectric crystal detector incorporating reference (C,) and test (CJ crystal sensors individually held in oscillating circuits (Or and 0 respectively) serviced by separate frequency counters (FC, and FCj, respectively) interfaced to a common microprocessor or other readout device. (Reproduced from [167] with permission of the American Chemical Society).

In all cases, a photomultiplier is used as the detector and, after suitable amplification, a variety of readout devices may be employed (see Section 2.2.5.3). 

Ellipsometer. An instrument for determining the thickness of very thin films of monomolecular dimensions. Essentially, the instrument is a polarization interferometer that utilizes a photometer as a readout device. 

Use an ammonia electrode (Orion Model 95-10, Beckman Model 39565 or equivalent) along with a readout device, such as a pH meter with expanded millivolt scale between -700 mV and +700 mV or a specific ion meter. The electrode assembly consists of a sensor glass electrode and a reference electrode mounted behind a hydrophobic gas-permeable membrane. The membrane separates the aqueous sample from an ammonium chloride internal solution. Before analysis, the sample is treated with caustic soda to convert any NH4+ ion present in the sample into NH3. The dissolved NH3 in the sample diffuses through the membrane until the partial pressure of NH3 in the sample becomes equal to that in the internal solution. The partial pressure of ammonia is proportional to its concentration in the sample. The diffusion of NH3 into the internal solution increases its pH, which is measured by a pH electrode. The chloride level in the internal standard solution remains constant. It is sensed by a chloride ion-selective electrode which serves as the reference electrode. 

A hand-held field PID consists of an air uptake pump, an ultraviolet (UV) ionization lamp, a photo multiplier, and a readout device. The air drawn in by the pump passes along the lamp, where organic compounds are ionized with UV light. The resultant current is converted into a signal proportional to the number of ionized molecules. The UV lamp is calibrated with a standard (isobutylene in air), and the readout device provides the vapor concentrations in parts per million-volume (ppm-v). UV lamps are sensitive to the presence of moisture high water vapor content in air will suppress their ionizing action. Some PID models have a moistureabsorbing filter that can be attached to the instrument s inlet. 

Procedure Use a Perkin-Elmer 403 atomic absorption spectrophotometer equipped with a deuterium arc background corrector, a digital readout device, and a burner head capable of handling 20% solids content. Blank the instrument with water following the manufacturer s operating instructions. Aspirate a portion of the Standard Preparation, and record the absorbance as As then aspirate a portion of the Sample Preparation, and record the absorbance as Av. Calculate the lead content, in milligrams per kilogram, of the sample taken by the formula... 

Manganese Detection Instrument Use any suitable atomic absorption spectrophotometer equipped with a fast-response recorder or other readout device and capable of measuring the radiation absorbed by manganese atoms at the manganese resonance line of 279.5 nm. 

An electronic measuring device is used for the measurement of quantities such as illuminance. It is composed of an amplifier, sensing device, filters, and a readout device. The ICH document does not specify which of the several different detector heads and filters available should be used. Photometric measurements are all weighed for human vision and as such do not measure the true amount of incident radiation. Table 1 listed the correction factors that are applied for a photometric detector and Figures 4 to 6 show how these corrections distort the actual data obtained (29). 

Analyse your samples replace the appropriate reference blank with a test sample,- allow the absorbance reading to stabilize (5-10 s) and read the absorbance value from the meter/readout device. For absorbance readings greater than one (i.e. < 10% transmission), the signal-to-noise ratio is too iOw for accurate results. Your analysis may require a calibration curve or you may be able to use the Beer-Lamfaert relationship (eqn [26.5]) to, determine the concentration of test substance in your samples. 

The essential components of an HPLC system are a solvent delivery system, a method of sample introduction, a column, a detector and an associated readout device (Fig. 32.16). 

The basic components of a spectrophotometer include (1) a light source (2) a means to isolate light of a desired wavelength (3) fiber optics (4) cuvets (5) a photodetector (6) a readout device (7) a recorder and (8) a microprocessor. 

---