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Accuracy:
Indicates how well a scale displays the correct results. Accuracy is the
ability of the scale or balance to display a value that matches the ideal value for a known weight.
Balance: A
weighing machine. The terms scale and balance are often used interchangeably.
Historically a balance was a device that determined mass by balancing an
unknown mass against a known mass as with a 2 pan assay balance. In modern
weighing machines balances are usually of the design that uses a force
restoration mechanism to create a force to balance the force due to the
unknown mass.
Baud
Rate: The
speed of communication when using the RS-232 interface with the scale. The greater the number
the faster the data is sent between the scale and the computer. Usually balances use 300 to
9600 baud.
Calibration:
The procedure to force the scale to display a certain value for
a known standard mass. Then any other mass will be determined using the
standard as the reference.
Capacity:
The maximum weight that can be placed on the balance or scale.
Check
Weighing: To
compare a weight against limits to determine if the weight is within preset
limits.
Density Determination:
Using a balance to determine the density of material, either
solids or liquids. (Density is the grams/cubic centimetre). If a solid
material is used it is weighed in the air and when suspended in a liquid. The
density can be determined either manually or in some balances by using special
software. To determine the density of a liquid a special float of known volume
is weighed in air and in the liquid.
Force
Restoration:
A method to determine an unknown mass by balancing the force
due to the mass with another force created by the system using coils mounted
in a magnetic field. Also called Servo motor or force motor.
Increment:
These terms are often used interchangeably to indicate how well a scale
displays the correct results. Increment is the value of the finest division of
the scale.
Levelling:
The procedure to set the balance so the platform is horizontal. This gives the
balance a position that is repeatable so the results will be the same if the
balance is moved. This is done using levelling feet.
Linearity:
The ability of a scale or balance to show the correct value throughout the
weighing range. Usually tested by placing known weights on the balance from
near zero to full capacity.
Load
Cell: See
Strain gauge load cell.
Mass:
Mass is a
physical property of a material. The mass gives a material weight when gravity
pulls the material toward earth. The units of mass are gram and kilogram. The
terms mass and weight are often used interchangeably.
Menu:
A set of
procedures that can be followed to change the characteristics of a balance.
The menu is made up of a number of options, called parameters, that can be set
at the factory or in some cases by the user.
Minimum Capacity:
The minimum weight that the scale or balance can accurately
measure within the tolerances specified.
Off
Center Loading:
The ability to display the same value when a weight is placed
anywhere on the weighing platform. Tested by weighing in the center of 4
quadrants on the platform. Also called eccentric loading or shift test.
Parts
Counting:
Using a scale to determine the number of parts placed on the platform based
upon the average piece weight. the piece weight is either entered by the user
or determined by weighing a sample on the scales.
Readability:
These terms are often used interchangeably to indicate how well
a scale displays the correct results. Readability is the value of the finest
division of the scale. Sometimes referred to as the smallest readable weight
value
Resolution:
Resolution is the value of the finest division of the scale. Sometimes
referred to as the smallest reading possible.
Repeatability:
The ability to display the same value when a weight is placed
on a scale more than one time. Often expressed as a standard deviation of 5 to
10 tests.
RS-232: A
method of sending data over wires. Often used to communicate between balances
and printers or computers.
Scale:
A weighing
machine. The terms scale and balance are often used interchangeably.
Historically a scale was a device that displayed weight by measuring a
deflection, such as a spring scale. In modern weighing machines scales are
usually using springs or strain gauge load cells.
Stability: A
scale is stable when the results do not change after a weight has been added
to the platform.
Stable
indicator: A
display that shows when the balance has determined the value displayed will no
longer change.
Strain
Gauge Load Cells:
A method to determine mass using a mechanical component that is
slightly bent by the addition of an unknown mass. the amount of bending is
measured by special resistors mounted on the load cell.
Tare:
To set a
display to show zero weight. This is used to remove the weight of any packing
or containers so that only the weight of the material within the container is
shown. The Tare value is deleted from the remaining weight that can be added
to a scale. For example if a scale has capacity of 500g and then 200g is tared,
the remaining capacity is 300g. Often Zero is used interchangeably.
Temperature Compensation:
The ability to correct any errors introduced to the weighing
system due to changes in temperature. Usually this correction is done in
software on precision balances and within the load cells of less accurate
scales.
Weighing: To
find the weight (mass) of an unknown against a standard known mass.
Weight: The
weight of a object is the result of gravity pulling a mass toward earth. When
a balance has been calibrated using a known mass then any unknown mass placed
upon the scale will have a weight proportional to the known mass. The units
gram and kilogram are often used to describe the weight of on object. It is
common for mass and weight to be used interchangeably. A weight can also be
any mass that is used, for example to put a weight on the scale.
Zero:
To set the display to show
zero weight. Used to reset the zero condition of a scale when small amounts of
material are on the platform. Zero does not take away from the capacity of a
scale. However it will only work in a very small range around the original
zero condition for the scale. Zero and Tare are often combined on one key, the
terms are often used interchangeably. | 
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