Performance Characteristics in Instrumentation and Control Systems

Performance characteristics
(a) static characteristics.
(b) dynamic characteristics.
  • Speed of response and measuring lag,
  • Fidelity and dynamic error,
  • overshoot,
  • Dead time and dead zone,
  • Frequency response.

(a) Speed of response and measuring lag:
Speed of response is defined as quick with which an instrument responds to change the value of quantity which is being measured.
Measuring lag refers to the delay in the response of an instrument to change in the input value.

(b) Fidelity and dynamic error:
Fedility is defined as the degree of closeness with which the instrument indicates or records the signal.
Dynamic error is defined as the difference between the indicated quantity and true value.

(c) Overshoot:
It is defined as the maximum amount by which the pointer moves behind the steady state.

(d) Dead time and Dead zone:
The time is defined as the time required for the instrument to begin to respond change the measure point.
Dead zone is defined as a largest change of the measuring to which the instrument does not respond.

(e) Frequency response:
Maximum frequency of the measuring variable of a instrument is capable of following the error.
Frequencies of the measured variable should not exceed 60% of the natural frequency of measuring instrument.