A digital sensor is an electronic or electrochemical sensor, in which data conversion and data transmission are performed digitally.
Sensors are often used for analytical measurements, ie measurement of chemical and physical properties of liquids. Parameters measured are usually pH, conductivity, oxygen, redox and other potential. Such measurements are used in the industrial world and provide important inputs for process control. Sensors are used to be analog types, but today more and more digital sensors are being used. This article explains the differences and reasons for the development of digital sensors.
Video Digital sensors
Aspek umum
Digital sensors are the modern successors of analog sensors. Digital sensors replace analog sensors gradually, as they overcome the traditional weaknesses of analogue sensor systems (cf chapter 3)
Maps Digital sensors
History
Electronic and electrochemical sensors are usually one part of the measuring chain. The measuring chain consists of the sensor itself, cable, and transmitter. In traditional analog systems, sensors change the measurement parameters (eg pH value) into analog electrical signals. This analog electrical signal is connected to the transmitter via cable. The transmitter converts the electrical signal into a readable form (display, current output, data bus transmission, etc.).
Sensors and cables are often not permanently connected, but through electrical connectors. The classic design with connectors and small current transmissions over these cables has four major drawbacks: a) Moisture and corrosion of the connectors falsify signals. b) Cables shall be protected and of exceptionally high quality to prevent the measurement signals altered by electromagnetic noise. c) The sensor can only be calibrated or adjusted when installed, because cable influence (length, ohmic resistance, impedance) can not be ignored. d) The cable length is limited.
Use and design
Digital sensors have been developed to overcome the traditional losses of analog sensors. Digital sensors are mainly used in water, wastewater and industrial processes. They measure parameters such as pH, redox potential, conductivity, dissolved oxygen, ammonium, nitrate, SAC, turbidity. The digital sensor system also consists of the sensor itself, cable, and transmitter. The differences in the analog sensor system are: a) The sensor has an electronic chip. The measurement signal is directly converted into a digital signal inside the sensor. Data transmission via cable is also digital. These digital data transmissions are not sensitive to cable length, cable or impedance resistance, and are not affected by electromagnetic noise. Standard cable can be used. b) The relationship between sensors and cables can be reached and done with inductive coupling. The associated moisture and corrosion is no longer a problem. Alternative fiber-optic cables can also be an option for long, unfriendly or electromagnetic connections. c) Sensors can be calibrated separately from the system.
References
- H. Galster: pH-Messung, VCH Verlagsgesellschaft mbH, ISBN 3-527-27836-2
- C.H. Hamann, W. Vielstich: Elektrochemie I, Verlag Chemie, ISBN 3-527-21039-3
- SchrÃÆ'¶ter/LautenschlÃÆ'¤ger/Bibrack: Taschenbuch der Chemie, Verlag Harri Deutsch, ISBN 3-8171-1472-9
- U. Tietze, Ch. Schenk: Halbleiter-Schaltungstechnik, Springer Verlag, ISBNÃ, 978-3-642-01621-9
Source of the article : Wikipedia
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