Changes for page How to do with Linear Calibration?

Summary

• Page properties (1 modified, 0 added, 0 removed)

Details

Page properties

Content

...	...	@@ -16,23 +16,17 @@
16	16	In some case, the measurement and real value are in different range, but they are both linear, we have to calculate the real value with the measurement we can use a simple Linear Calibration.
17	17
18	18
19		-**Example:** we have a water level probe, the measurement range is 0 ~~ 10 meters, and the output is 4~~20mA, this means the when the water level is 0 meter, the output is 4mA, when the water level is 10 meters, the output is 20mA.
	19	+Example: we have a water level probe, the measurement range is 0 ~~ 10 meters, and the output is 4~~20mA, this means the when the water level is 0 meter, the output is 4mA, when the water level is 10 meters, the output is 20mA. We can make a coordinate axis as below:
20	20
21		-We can make a coordinate axis as below:
	21	+1. Y axis is the real value, from 0 ~~ 10 meters
	22	+1. X axis is the probe output , from 4~~20mA
22	22
23		-1. (% style="color:blue" %)**Y**(%%) axis is the real value, from 0~~10 meters
24		-1. (% style="color:blue" %)**X**(%%) axis is the probe output , from 4~~20mA
	24	+We use two points to make the linear line: point1(x1,y1) = (4,0), point2(x2,y2)= (20,10). Since the reading is linear, all probe output and real value is on this line, so we can calculate the real value by probe output in two steps:
25	25
26		-We use two points to make the linear line: Point1(x1,y1) = (4,0), Point2(x2,y2)= (20,10).
	26	+Step1: Get k(Slope) for the line: k=(y2-y1)/(x2-x1) = (10-0)/(20-4) =10/16= 0.625
27	27
28		-Since the reading is linear, all (% style="color:blue" %)**probe output**(%%) and (% style="color:blue" %)**real value**(%%) is on this line, so we can calculate the real value by probe output in two steps:
	28	+Step2: Get real value ( y ):
29	29
30		-* **Step1:** Get (% style="color:blue" %)**k(Slope)**(%%) for the line:
31		-
32		- k=(y2-y1)/(x2-x1) = (10-0)/(20-4) =10/16= 0.625
33		-
34		-* **Step2:** Get (% style="color:blue" %)**kreal value(y)**(%%):
35		-
36	36	k=(y-y1)/(x-x1)
37	37
38	38	~-~-> y = k*(x-x1)+y1 = 0.625 * (x-4) + 0.
...	...	@@ -39,7 +39,7 @@
39	39
40	40	~= 0.625 * (x-4)
41	41
42		-When x=12mA , y=5 meters
	36	+When x=12mA , y=5 meters
43	43
44	44	When x=8mA, y= 2.5 meters
45	45
...	...	@@ -86,4 +86,6 @@
86	86
87	87
88	88
	83	+
	84	+
89	89