PIC TEST 1 Flashcards
manometer principle
Changes in pressure will cause a liquid to rise or fall in a tube
Manometer advantages
Low cost
simple and easy to use
Bourdon tubes principle
A curved tube will straighten out when pressure is applied to the inside of the curve
Diaphragm principle
When pressure is applied to one side of the diaphragm, it deform.
Bellows principle
One end attached to the tranducer case and the other end is free to move. pressure detected, it will expand causing free end to move.
4 basic components
controller,controlled variables,sensor,control element
hystheris
where the accuracy of the device is dependent on the previous value and the direction of variation
Accuracy can be expressed as:
-error in units of the measured value
-percent of upper range
-percent of scale length
-percent of actual output value
Zero of instrument
the lowest-value measure by the instrument
Range of instrument
the high and low operating limits between which the device will operate correctly
linearity
how close the curve is to the straight line
repeatability
how close the second measurement to the first one under the same condition and same input
Calibrate
to configure a device so that required output represent the respective input
Ramp
defines the delayed and accumulated response at the output for a sudden change in the input
set point
represent the unit of the process variables and is used by the by the controller as reference to determine the output of the process
