Types of Error in transducers

 The error is mainly due to noise in input or output levels. It changes the performance of internal and external parameters. The transducer has an error because it does not follow in many circumstances. Relationships between its input and output 

              q₀ = f(qi).  ..,..(i)

If there is a departure in the above relationship, it results in 'error'

    for example . Output is available on the account of the input, but the output is obtained in practice, then the error of the device 

                ɛ = q₀ – q₀

Transducers express error (ɛ) in terms of the form of input or output quantity.

What is Transducer ?

The following are the major errors generated in the truducer -

(i) Scale Error - Following are the major types of scale error in transducers

1. Zero Error - In this case the output error is completed by the correct value by a constant factor within the entire range of the transducer.             
2. Sensitivity Error - A sensitivity error is present where the erroneous output is observed by the constant value by the constant value.  Suppose the correct output is 10 but the output should be Kq, K is a constant.  The transducer sensitivity error is shown in the figure with the help of a curve.   
   
3. Non-Conformity - When the transducer function is different from the theoritical transducer function for all values of the input, this type of error is called the nonconformity error, shown in the figure.                   
   
4. Hysteresis - All transducers are subject to the effects of hysteresis.  The output of the transducer does not depend only on the input quantity, while the input quantity is applied first.  Hence, the output obtained at the input quantity of the same value is different.  In addition, the output received is high and low.  More or less hysteresis in the transducer is shown in Fig.  

(ii) Dynamic Error - Only the dynamic error is generated when the input quantitation of the transducer changes over time.  This energy storage element is present at the factory amount of the presence systems, due to which the change in the output of the time lag according to the input is not uniform.  

                       In any transducer circuit, energy storage element C is combined in series with resistance R.  If step input of magnitude E is applied in this RC series circuit, after some time the across voltage of the capacitor.                     ec = E[1 -exp(–t/τ)]                                Where,τ = time constant = RC dynamic or measurement error                     em(t) = E– ec                                                                         = exp (– t /τ)                                        The small time constant present or measurement error is also small.  Dynamic error is a time function.  Increased dynamic error also decreases after applied input

Steady State Error                                       ess = em(t), t →∞  

(iii) Error due to change of Frequency – Frequency response and high frequency cut-off are two specifications that disassemble the response of the transducer for the application variable frequency sine wave input.

The sine wave input is derived from the sine wave output. As the frequency of the sine wave input increases, the output from the transducer also takes less time. After a perticular frequency, the transducer does not immediately respond to the larger response, with the sinusoidal input being altered. Thus the output of the transducer is small and the phase shift between input and output increases. Therefore, as the frequency increases, the output of the transducer decreases. The frequency response of the transducer is shown in the figure.

The vertical response of the transducer's response response is that the horizontal axis gains and horizontal stimulus attracts someone. Gain is the ratio of input to output. Specifies in terms of mon decibels. Therefore 

gain = 20log (output / input) 

= 20log (q₀ / qi) in db 

The frequency response curve consists of plots on a frequency logarithmic scale that covers a wide range of frequencies.

(iv) Error due to Noise and Drift –

The noise and drift signals arising from the transducer are very variable over time. These noise and drift signals are superimposed on the output signals. A signal of random amplitude and random frequency is present in the noise signal. The drift has slow change over time. Normally the noise and drift input signal is independent of magnitude.

The drift is a characteristic of the gradual shift in transducer output from the original position relative to time. The error generated by the drip is only dependent on the output of the transducer. It is not dependent on the input condition.