Calibration

Question 1

What is calibration?

Answer 1

-The process of testing and modifying a device (sensor) to make sure that it is taking accurate/correct readings.
-To calibrate a sensor you need a calibration reference (standard against which you calibrate).

Question 2

Simple method of calibration

Answer 2

-To test readings against another sensor so you know it is calibrated, readings should be the same.

Question 3

Physical method of calibration

Answer 3

-Physical reference, a ruler or measuring tape to find out if an item should trigger (proximity sensor) so it’s the correct distance.

Question 4

What is a characteristics curve?

Answer 4

-Each sensor has a characteristics curve which maps the sensors response in comparison to the ideal response.

Question 5

What are the 3 curves: catagories of results given by a sensor?

Answer 5

-Offset: reading is higher or lower than ideal.
-Sensitivity: readings change at a higher rate to the ideal.
-Linearity: readings are directly proportional to the ideal.

Question 6

Types/points of calibration

Answer 6

-One point calibration: used to correct offset.
-Take a single reading, if reading too high or low, they can then calibrate a single reading to be closer to ideal.

Question 7

How?

Answer 7

-take the reading with sensor
-compare the reading to ideal response
-subtract the reading from the ideal and this gives offset
-add offset to every reading to get the calibrated value

Question 8

What is two point calibration?

Answer 8

-Used to correct both offset and sensitivity (two readings)

Question 9

How?

Answer 9

-Compare the readings to the ideal response
-Calculate the range from the sensor value (subtract the low from the highest)
-Calculate the range from the ideal response
-Formula used to correct the value

Question 10

What is multi-point calibration?

Answer 10

-Uses many different readings (at least 3) used to increase the accuracy of the calibration