Types of Encoder

Types of Encoder: Types of Encoder – By the use of a digital code, it is possible to identify the position of a movable test piece in terms of a binary number. The position is converted into a train of pulses. This is achieved by a digital transducer and is also termed as encoder. Since […]

Electromechanical AD Converter

Electromechanical AD Converter: Another area of application in which Electromechanical AD Converter is very important, involves the translation of the angular position of a shaft into digital information. (A very common application of this type of conversion is found in large radar installations, where the azimuth and elevation information are determined directly from the shaft […]

Sensors Based Computer Data Systems

Sensors Based Computer Data Systems: This Sensors Based Computer Data Systems describes hardware/software which is commercially available at several levels of completeness, ranging from single board computer “front ends” to stand alone system and high level programming languages. Even the simplest and least expensive devices require considerable electro­nics/computer expertise on the part of the user, […]

Data Logger Operation

Data Logger Operation: Data Logger Operation – For proper understanding of a Data Logger Operation, it is essential to understand the difference between analog and digital signals. For example, measurement of temperature by a milli voltmeter, whose needle shows a reading directly proportional to the emf generated by the thermocouple, is an analog signal. However, […]

Data Loggers Function

Data Loggers Function: The basic Data Loggers Function is to automatically make a record of the readings of instruments located at different parts of the plant. Data loggers measure and record data effortlessly as quickly, as often, and as accurately desired. Measurement errors are eliminated and the log is permanent in a form most suited […]

DA Converter Working Principle

DA Converter Working Principle: The resistive divider or ladder can be used as the basis for a DA Converter Working Principle. It is in the resistive network that the actual translation from a digital to an analog signal voltage takes place. However, there is a need for additional circuitry to complete the design of a […]

Weighted Converter Using Transistor Switches

Weighted Converter Using Transistor Switches (Current Switch): Figure 17.19 (a) shows a circuit diagram of a weighted converter, using transistor switches. When the D bit is high (logic 1), it produces enough base current to saturate the transistor. When the D bit is low (logic 0), the base current is zero and the transistor remains […]

Binary Ladder Circuits

Binary Ladder Circuits: A Binary Ladder Circuits is constructed of resistors having only two values and thus overcomes the disadvantages of weighted resistors. The left end of the ladder is terminated in 2 R, as shown in Fig. 17.14. Assuming that all digital inputs are at ground, beginning at point A of Fig. 17.14, the […]

Computer Based Data Acquisition System

Computer Based Data Acquisition System: Computer Based Data Acquisition System – If a large number of inputs are to be measured, some equipment is needed to measure them and display the results in a meaningful and operationally useful fashion. All this is possible with Data Acquisition System, which utilises a computer driven visual display unit […]

Multi Channel Data Acquisition System

Multi Channel Data Acquisition System: The Multi Channel Data Acquisition System can be time shared by two or more input sources. Depending on the desired properties of the multiplexed system, a number of techniques are employed for such time shared measurements. Multi-Channel Analog Multiplexed System: The multi-channel DAS has a single A/D converter preceded by […]

Single Channel Data Acquisition System

Single Channel Data Acquisition System: A Single Channel Data Acquisition System consists of a signal conditioner followed by an analog to digital (A/D) converter, performing repetitive conversions at a free running, internally determined rate. The outputs are in digital code words including over range indication, polarity information and a status output to indicate when the […]

Signal Conditioning of Inputs

Signal Conditioning of Inputs: Since all the data that have to be acquired, do not generally originate from identical sources, signal conditioning becomes necessary in some cases. A simple attenuator, is used to scale down the input gains, this is to match the input signal level to the converter’ full scale range. Linearisation of the […]