Instrumentation front panel

The ammeter provides an internal calibration circuit consisting of a mercury battery and appropriate resistors. The calibration is performed by adjusting potentiometers located on the instrument front panel to a corresponding calibration signal read properly on the read-out meter. 

LabVIEW Front Panel display (top) of photomultiplier count rate in counts per second (cps) and block diagram (bottom) for a Virtual Instrument (VI) that measures this. The VI is used to count scattered photons using a counter (ctrO) on a National Instruments M622at PC board and is useful in optimizing die imaging optics and for ensuring adequate count levels for the experiment. 

LabVIEW Front Panel display of g/function (top) and block diagram (bottom) for a Virtual Instrument (VI) for dynamic light scattering measurements. 

Automatic specimen introduction requires the development of mechanical interfaces between each laboratory analyzer and devices such as conveyor belts, mobile robots, or robot arms. Enhancements to electronic interfaces for laboratory instruments are necessary to allow remote computer control of front-panel functions, notification of instrument status information, and coordination of the distribution of specimens between instruments. Most existing LIS interfaces with laboratory analyzers provide only the ability to download accession numbers and the tests requested on each specimen, and to upload the results generated by the analyzer. 

Spectrometer control. We prefer dual control wherein the instrument can alternatively be addressed from the front panel or a keyboard. Spectrometer control by computer permits the convenient acquisition of huge amounts of data by systematic variation of experimental parameters. 

Figure 7. Software simulation of the front panel of the Varian 875 Atomic Absorption Spectrometer. All functions operate when activated by the mouse as if activated on the instrument itself.

FIGURE 3.1 CAM AG TLC-MS interface. The three controls on the top front panel are laser on/off button (upper), plunger np/down button (middle), and cleaning switch (lower). The moving lever on the right side is the on/off connection valve used to start the solvent flow into the MS instrument. (From Advion, Inc., Ithaca, New York. With permission.)... 

Control and monitoring. Microprocessors have been integrated into scopes to reduce the number of mechanical switch contacts, which are prone to failure, and to permit front-panel setting recall capabilities. Auxiliary signal outputs are available to feed other instruments, such as a distortion analyzer or frequency counter. 

Auto-ranging. Many instruments wiU automatically adjust for optimum sweep, input sensitivity, and triggering. The instrument s microprocessor automatically configures the front panel for optimum display. Such features permit the operator to concentrate on making measurements, not on adjusting the scope. 

A spectrum analyzer intended for use at RF frequencies is shown in block diagram form in Fig. 20.62. The instrument includes a superheterodyne receiver with a swept-tuned local oscillator (LO) that feeds a CRT display. The tuning control determines the center frequency (Fc) of the spectrum analyzer, and the scan-width selector determines how much of the frequency spectrum around the center frequency will be covered. FuU-feature spectrum analyzers also provide front-panel controls for scan-rate selection and bandpass filter selection. Key specifications for a spectrum analyzer include... 

FIGURE 4-18 LabVlEW front panel for a data-acpuisition system allows the user to choose parameters such as sampling rate, sample length, and filtering values. (Reprinted with permission ot National Instruments Corporation.)... 

The front panel of the casing of the instrument contains the adjustment and control units (control switches for the UV lamps (254 nm and 366 nm), timing unit, and temperature), with a keyboard of the sensor type, as well as the power switch for the instrument, and the switch for the nitrogen overpressure with a manometer (0-2.5 bar). The rotation speed may be varied between 80 and 2000 rpm in steps of 10 and 100 rpm. 

A front panel switch allows checking the alarm point and the high voltage, as well as selection of range. The instruments are operated on the XI range, with the time constant control set to maximum time constant. The detectors are operated at 900VDC. Alarm setpoints are noted on the individual instruments. 

Figure 16 Schematic diagram of Rotachrom model P. (1, upper part of the stationary chamber 2, collector 3, tubes in the collector 4, glass rotor S, stationary phase 6, vapor space 7, fixing screw 8, solvent delivery system 9, safety glass 10, UV lamp (254 nm) 11, UV lamp (366 nm) 12, motor shaft with tube 13, motor 14, lower part of the stationary chamber 15, casing of the instrument 16, front panel for adjusting and controlling units with keyboard 17, eluent outlet.

Figure 5.1 Front panel of the virtual instrumentation of temperature measurement system.

Figure 5.25(a). Further, Figure 5.25(b)—(d) show the block diagram of the virtual electrochemical NO analyzer, front panel with block diagram of the potential sweep, and front panel with block diagram of the process of the virtual electrochemical NO analyzer. The overall electroanalytical performance of the virtual electrochemical NO analyzer was compared with the standard cyclic voltammetry instrument as shown in Table 5.1. 

Figure C.8 The front panel of the Virtual Instruments (VI) for the interactive FID control tuner (www.che.utexas.edu/course/che360/documents/tuner/Process Tuner.html).

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