Chapter 6 area & volume measurement, Digital Planimeter

Especially for Polytechnic Students

1. Unit 6: Measurement of Area and Volume
6.1DigitalPlanimeter:ComponentsusesofDigitalPlanimeter:
mponempone
Components:
1)Roller
2)TracingArm
3)TracingMagnifier
4)TracingPoint
5)FunctionKeys
6)Display
Prepared by-Abhay Abhale

2. Unit 6: Measurement of Area and Volume
6.1DigitalPlanimeter:ComponentsusesofDigitalPlanimeter:
FunctionKeys:
i.ON–Toontheinstrument,tostartthemeasurement.
ii.OFF–Toofftheafterthemeasurementisover.
iii.START-Tostartthetracingonareaboundary.
iv.UNIT-1–Tosetunitofareainverticaldirection.
v.UNIT-2-Tosetunitofareainverticaldirection.
vi.Scale–Tosetthescaleasperscaleofmaptobetrace.
vii.AVER–Tofindcumulativeaveragetogetbetter
accuracy
viii.MEMO–ToTemporarystoretracedareainsidethe
Planimeter.
ix.HOLD–Toholdthereading,sothataftermovement
oftracingmagnifierreadingwillnotbecounted.
x.0-9NUMBERKEYS–Togiveinputforscaleetc.
Roller
Tracing Magnifier
Display
Function Keys
Tracing Arm
Prepared by-Abhay Abhale

3. Unit 6: Measurement of Area and Volume
6.2MeasurementofareausingdigitalPlanimeter:
i.Keepthedrawingsheetonlevelhorizontalsurface.
ii.PressONkeyanddisplayindicatezero'O‘.
iii.Selectthescalebypressing,'SCALEkey.
iv.Presstheunitkeyandselecttheunit.
v.Markthestartingpointonoutlineofarea.
vi.Setthetracingpointofmagnifyingcircleonstartingpoint.
vii.Press'START'keyanddisplaywith'O'andbeepsound.
viii.Movethetracerclockwisealongtheoutlineorperipheryofthearea.
ix.Aftercompletingonerotationthetracingpointcomesagainststartingpoint
press‘HOLD'keyandobservethereadingondisplay.
x.Thiswillgivesareaonthedisplay.
xi.Forbetteraccuracypress‘AVER’then‘HOLD’andagainstarttracingfrom
startingpoint.
xii.Forlargerareadivideitintonumberofsub-areasandtakemeasurementof
eachareaanaddit.
Prepared by-Abhay Abhale

4. Unit 6: Measurement of Area and Volume
6.3Measurementofvolumeofreservoirfromcontourmap.
i.ComputationofVolumePrizmoidalFormulaVolume,
V=L/3x[A
1+A
n+2(A
3+A
5+…..A
n-2)+4(A
2+A
4+A
n-1)]
i.e.Volume=CommonDistance/3x[AreaofFirstSection+AreaofLastSection+2
(SumofAreaofOddSections)+4(SumofareasofevenSection)]
Inshort,
Prepared by-Abhay Abhale

5. Unit 6: Measurement of Area and Volume
6.3Measurementofvolumeofreservoirfromcontourmap.
i.ComputationofVolumeTrapezoidalRule(AverageEndAreaRule)
Volume(CuttingorFilling)
V=d/2[A
1+A
n+2(A
2+A
3+…….A
n-1)
i.e.Volume=CommonDistance/2[Firstsectionarea+Lastsectionarea+2(
sumofareasofothersections)
Inshort,
Prepared by-Abhay Abhale

6. Unit 6: Measurement of Area and Volume
6.3SimpleNumerical
Problem
(*Notinsyllabus)
A
1
A
3A
2 A
4 A
5
Prepared by-Abhay Abhale