Factors that influences while choosing a Transducers

transducer
instrumentation

#1

Transducers are often employed at the boundaries of automation, measurement, and control systems. Before choosing a transducer we have to ensure that the transducer is suitable for our need. These are factors which may influence the selection.

Operating principle:

There are operating principles such as resistive, inductive, capacitive, piezoelectric, photo-voltaic, ionization etc.,
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Sensitivity:

Transducer must be sensitive enough not to give an output, but to give an detectable output.

Operating range:

A transducer should have good resolution over it’s entire range of operation. We cannot choose a temperature sensing transducer that work in range 0-100 degree Celsius for a use in boiler where temperature is up to 1000 degree Celsius, that’s what it means.

Accuracy:

High degree of accuracy is needed and small value of repeatablity.

Cross-sensitivity:

Cross-sensitivity must taken into account while measuring mechanical quantity. Cross-sensitivity must reduced. Because when transducer subjected to measure variations in one plain, while actual quantity to be measured is in another plain.

Error:

A transducer must avoid error. For which a transducer should maintain expected input output relationship by it’s transfer function.

Transient & Frequency response:

Transducer should meet desired time domain specifications such as peak over shoot, raise time, setting time & small dynamic error, it should flat frequency response curve with higher cut-off frequency at high limit in-order to have a high value.

Loading effect:

Transducer should have high input impedance and low output impedance to avoid loading effect.

Environment compatibility:

Under specified environment conditions the transducer maintain input-output relationship and doesn’t breakdown. Transducer should be able to withstand temperature, pressure shock etc., when subjected to it, if it is application require so.

Insensitivity to unwanted signals:

Noise should be avoided in measuring, so that a good transducer should insensitive to unwanted signals. But high sensitive to desired signals.

Usage and ruggedness:

Ruggedness both of mechanical and electrical intensities of transducer VS it’s size and weight must be considered while selection.

Electrical aspects:

Length and type of cable required must be considered.
Signal to noise ratio must be taken care.
Frequency response limitation must be taken to account.

Stability & reliability:

Should have high degree of stability during it’s operation & storage life. Reliability should be assure in case of failure of transducer in-ordered that functioning of the instrumentation system continues uninterrupted.

Static characteristics

Apart from low static error transducers should have a low non linearity, high resolution, and a high degree of repeat-ability. Transducer selected should be free from temperature effect and load alignment effects. it should not need frequent calibration.