Load Cell Terminology

Ambient Conditions

The conditions (humidity, pressure, temperature, etc.) of the medium surrounding the load cell.

Ambient Temperature

The temperature of the medium surrounding the load cell.

Angular Load Eccentric

A load applied eccentric with the primary axis at the point of application and at some angle with respect to the primary axis.

Angular Load Concentric

A load applied concentric with the Primary axis at the point of application and at some angle with respect to the Primary axis.

Axial Load

A load applied along or parallel to and concentric with the primary axis.

Calibration

The comparison of load cell outputs against standard test loads.

Calibration Curve

A record (graph) of the comparison of the load cell outputs against standard test loads.

Combined Error

(Non linearity and Hysteresis) The maximum deviation from the straight line drawn between original no-load and rated load outputs expressed as percentage of the rated output and measured on both increasing and decreasing loads.

Compensation

The utilization of supplementary devices, materials, or process to minimize known sources of error.

Creep

The change in load cell output occurring with time while under load and with all environmental conditions and other variables remaining constant.

Creep Recovery

The change in no-load output occurring with time after removal of A load which had been applied for a specific period of time. Usually measured over a specific time period immediately following removal of rated load and expressed as a percent of rated output over a specific period of time.

Deflection

The change of length along the primary axis of the load cell between no-load and rated load conditions.

Drift

A random change in output under constant load conditions.

Eccentric Load

Any load applied parallel but not concentric with the primary axis.

Error

The algebraic difference between the indicated and true value of the load being measured.

Excitation, Electrical

The voltage or current applied to the input terminals of the load Cell.

Frequency Response

The range of frequencies over which the load cell output will follow the sinusoidally varying mechanical input within specified Limits.

Hysteresis

The maximum difference between load cell output readings for the same applied load; one reading obtained by increasing the load from zero and the other by decreasing the load from rated output.

Insulation Resistance

The dc resistance measured between the load cell circuit and the load cell structure. Normally measured at fifty volts and under standard test conditions

Load

The weight or force applied to the load cell.

Load Cell

A device which produces an output signal proportional to the applied weight or force.

Natural Frequency

The frequency of free oscillations under no-load load conditions.

Nonlinearity

The maximum deviation of the calibration curve from a straight line drawn between the no-load and rated outputs; expressed as a percentage of the rated output and measured on increasing load only.

Output

The signal (voltage, current, pressure, etc.) produced by the load cell. Where the output is directly proportional to excitation, the signal must be expressed in terms of volts per volt, per ampere, etc., of excitation.

Output, Rated

The algebraic difference between the outputs at no-load an at rated load.

Overload Rating, Safe

The maximum load in percent of rated capacity which can be applied without producing a permanent shift in performance characteristics behond those specified.

Overload rating, Ultimate

The maximum load in percent of rated capacity which can be applied without producing a structural failure.

Primary Axis

The axis along which the load cell is designed to be loaded; normally its geometric centerline.

Rated Capacity (Rated Load)

The maximum axial load the load cell is designed to measure within its specifications.

Reference Standard

A force measuring device whose characteristics are precisely known in relation to a primary standard.

Repeatability

The maximum difference between load cell output readings for repeated loadings under identical loading and environmental conditions.

Resolution

The smallest change in mechanical input which produces a change in the output signal.

Sensitivity

The ratio of the change in output to the mechanical input.

Shunt Calibration

Electrical simulation of load cell output by insertion of known shunt resistors between appropriate points within the circuitry.

Shunt-To- Load Correlation

The difference in output readings obtained through electrically simulated and actual applied loads.

Side Load

Any load acting 90 degrees to the primary axis at the point of axial load application

Stabilization Period

The time required to insure that any further change in the parameter being measured is tolerable.

Standard Test Conditions

The environmental conditions under which measurements should be made when measurements under any other condition may result in disagreement between various observers at different times and places. These conditions are as follows: Temperature 23 degrees +or- 2 degrees C (73.4 degrees +or- 3.6 degrees F

Temperature Effect On Rated Output

The change in rated output due to a change in ambient temperature.

Temperature Range Compensated

The range of temperature over which the load cell is compensated to maintain rated output and zero balance within specific limits.

Temperature Range Safe

The extremes of temperature within which the load cell will operate within permanent adverse change to any of its performance characteristics.

Terminal Resistance Corner To Corner

The resistance of the load cell circuit measured at specific adjacent bridge terminals at standard temperature, with no load applied, and with the excitation and output terminals open-circuited.

Terminal Resistance Input

The resistance of the load cell circuit measured at the excitation terminals at standard temperature, with no load applied and with the output terminals open-circuited.