Specifications

METTLER TOLEDO Weigh Module Systems Handbook
(12/99)15-2
Live Load — The downward force exerted by an object or material being weighed on a
scale.
Live-to-Dead Connection — A mechanical connection between a scale and an object
that you do not want to weigh. A common example is piping connected to a tank scale.
If the connection is not flexible enough to allow the scale to move freely, the piping can
push or pull on the scale and produce inaccurate weight readings.
Load — A mechanical force applied to a scale or other object.
Load Cell — The component of a scale that detects the mechanical force exerted by a
weight and converts it to an electrical signal.
Potted Seal — A layer of organic sealing compound used to protect the strain gauges in
a load cell. It is not as effective as a hermetic seal, which is often preferred for harsh
environments.
Radio Frequency Interference — The disturbance of an electrical device’s operation that
is caused when the device picks up radio frequency emissions from an outside source.
Rated Capacity — The heaviest load that a scale is designed to withstand under normal
conditions.
Repeatability — a scale’s ability to display a consistent weight reading each time the
same weight is placed on the scale. It is especially important for batching and filling
applications, which require that the same amount of a material be used for each batch.
Resolution — A scale’s ability to detect changes in weight. For a digital scale, resolution
is measured in increment size, which is the smallest weight change that the scale can
detect.
Safe Overload — The maximum weight that can be applied to a load cell without
causing it to fail (typically 150% of rated capacity).
Seismic Loading — Forces exerted on a scale or its support structure by earthquakes or
other vibrations of the earth.
Shear Force — A horizontal force exerted on a scale.
Shock Loading — Forces exerted on a scale or its support structure when an object
strikes it. Shock forces can be created when an object is dropped on a scale or when a
vehicle runs into a scale
Spring Rate — A measure of a material’s flexibility. The spring rate constant for a load
cell is its rated capacity divided by load cell deflection at rated capacity.
Static Loading — A situation in which the load applied to a scale will be weighed while
not in motion.
Strain Gauge — A wire or series of wires that measures the strain a force exerts on an
object. When a strain gauge is attached to a load cell, it measures how much a weight
causes the load cell to deflect. The strain gauges stretches as the load cell deflects,
increasing the wire’s resistance to an electric current being transmitted through it.
Tension — The act of stretching a material. A tension weigh module is designed to
stretch as weight is applied to it.
Transducer — A device used to convert energy from one form to another. A load cell is a
transducer that converts a mechanical force (weight) to an electrical force (current)
which can be used to provide a digital weight reading.
Type Evaluation — The procedure used to test a particular type (or model) of weighing
device. In the United States, the National Type Evaluation Program (NTEP) tests a
sample of each model of scale. If the tests show that a scale complies with the