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What is Calibration?•

Standardization of measuringinstrument: the checking of a

measuring instrument againstan accurate standard to

determine any deviation andcorrect for errors.

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• is a comparison between

measurements –

one of known magnitude or

correctness made or set withone device and another

measurement made in assimilar a way as possible with

a second device.

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PLATFORM SCALE

andBALANCE SCALE

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Platform Scale

• is a weighing machine

with a platform to holdthe object or objects

being weighed.

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• A platform scale is a very

versatile scale and canweigh a wide range of 

objects for you. They areused where massive

objects or large quantitiesare to be weighed.

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• These scales often have a readout

that is on a post or other towerthat rises above the platform -

often to viewing height.

Alternatively, they may be

connected electronically to a

readout on a remote panel inorder to view the readings more

conveniently.

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Balance Scale 

• is an instrument used to

measure the weight of objects by comparing their

weights to a set of knownweights.

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• Other types of scales are affected

by gravity and, depending upongeographic location, can vary in

their results. Balance scales do

not have this issue because they

are balanced, which implies both

sides of the scale are affectedexactly the same.

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Factors AffectingAccuracy

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1. Load cell accuracy

2. Load factors

3. Environmental forces4. Instrumentation and

control

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• Reference weight has error

in mass.

• Scale is pushed up and

down by even small air

gusts.

Balance Scale

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• Drift in the circuit's accuracy

or change in temperaturecauses miscalibration.

• Due to thermalcontraction/expansion of 

components misalignment ininstrument occurs.

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• Equilibrium position of 

components having friction andthat, which is frictionless, is

different.

• Evaporation of water from wet

items

• Convection of air from hot or

cold items.