Instrumentation Control System
- Measurement
- Control
Measurement is the process of comparing a quantity in the system against the standard or reference
Standar Measurement
Measurement System :
DIRECT MEASUREMENT (DIRECT)
is a measurement system that can be read directly on the place where the measurement is made. Example: temperature measurement, height, body weight, etc..
INDIRECT MEASUREMENT (INDIRECT)
is a measurement system that can be read from elsewhere or remotely from the object being measured, thus requiring more devices.
FLUID TEMPERATURE CONTROL BY STEAM HEAT CLOSED SYSTEM (CLOSE LOOP)
CLOSED SYSTEM (CLOSE LOOP)
Terminology Specifications :
Measured Variable / Magnitude Measured
Is a quantity of physical measurements, such as pressure, flow, level (level), temperature, etc..
Measured Signal / Signal Measured
Variables generated by a sensor / sensing element. The signal can be shaped pneumatic, electric, hydraulic.
Range (Area Measurement)
The area bounded by a minimum price and a maximum price of a quantity being measured.
Span (Regional Measure)
The difference between the minimum and maximum limits of the measurement area
Elevation Zero (Zero Elevation)
A price that states how high the price scale above absolute zero lower bound of the price scale is concerned.
Suprresed Zero
A price that states how much the price scale absolute zero below the price limit of the scale is concerned.
Sensitivity or Gain
Comparison between changes in output to increase at a steady state input / steady state.
Accuracy
A measure that tells us how much the instrument showed that prices deviate from the actual price.
Error
The difference between the actual price of the price indicated by the instrument.
hysteresis
A state in which the trajectory calibration when input prices going up is not the same as when the input trajectory derived calibration.
Dead band
An area measuring (state) in which the input changes do not result in a change in output.
Repeatability
Measure of the extent to which the instrument can show the same output for a fixed input, if measurements are made over and over - again.
Deviation
Deviation of the price or the expected trajectory
linearity
A measure of how much the line or path calibration input / output of an instrument is a straight line.
Drif
Changes in the relationship of input / output in a given time period to the time change.
tangent
A condition of a motion oscilasi weakening of a signal (output) systems.