Analogue measuring devices

Other Measuring Devices. One of the most valuable devices in the arsenal of electrical measurement is the oscUloscope, which is available in both analogue and digital models. Like a typical meter, the oscilloscope measures electrical inputs, but it also has the capability to display the reading as a dynamic trace on a display screen. The screen is typically a cathode-ray tube (CRT) display, but later versions use liquid crystal display (LCD) screens and even can be used with desktop and laptop computers. 

The reactor protection system shown in Fig. 8 monitors important process parameters of the research reactor on a redundant and diverse basis. If a process parameter ex-ceeds or falls below the set limit (on two out of three modes), the reactor is automatically shut down and further protective functions are initiated if necessary. In order to improve the operational safety of the research reactor still further, a diversified "flow measurement device for the secondary cooling circuit" to assist "temperature measurement in the primary circuit" was added to the protection system, and the three binary transmitters for the measuring point "water level, basement" were replaced by three analogue, selfmonitoring measuring channels. It is also planned to replace the three redundant measuring channels for "water level in the pool by three channels that would not fail in an operational emergency. 

In addition, most devices provide operator control of settings for temperature and/or response slope, isopotential point, zero or standardization, and function (pH, mV, or monovalent—bivalent cation—anion). Microprocessors are incorporated in advanced-design meters to faciHtate caHbration, calculation of measurement parameters, and automatic temperature compensation. Furthermore, pH meters are provided with output connectors for continuous readout via a strip-chart recorder and often with binary-coded decimal output for computer interconnections or connection to a printer. Although the accuracy of the measurement is not increased by the use of a recorder, the readabiHty of the displayed pH (on analogue models) can be expanded, and recording provides a permanent record and also information on response and equiHbrium times during measurement (5). 

Accurate temperature measurements in real-life situations are difficult to make using the KTTS. Most easily used thermometers are not thermodynamic that is, they do not operate on principles of the first and second laws. Most practicable thermometers depend upon some principle that is a repeatable and single-valued analogue of temperature, and they are used as interpolation devices of practical and utilitarian temperature scales which are themselves... 

This technique is of high accuracy and is meant to be used in precision measurement instrumentation, for it is inherently insensitive to the DC-offset and the AC-noise in the sinusoidal signal which can be substantially reduced by a great variety of electronic devices ranging from various electronic analogue filters, and digital filters to the most effective lock-in amplifiers. 

The maximum intensity at which a counter can operate is determined by the dead time set by the electronics. In the case of an analogue device such as the television detector the detector can saturate in terms of the cumulation of charge in a picture element (pixel). The gain of the system can be reduced to allow these strong signals to be measured but to... 

Traditionally controllers were complex mechanical devices operated pneumatically and many pneumatic controllers still exist in industry. More recently, analogue electronic controllers have been used but these are now superseded by various digital control devices (see section 7.7.6). Details of controller hardware operation are given by Johnson. The controller compares the signal representing the measured value with the setpoint (i.e. desired) value of the variable. The control action depends on the control mode selected for the controller. 

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