Force sensor

01

Read capacity and rated output

A&D, a weighing equipment maker, defines rated capacity as the largest load a load cell can measure while meeting its specifications, and rated output, also called span, as the difference between no load and rated load, which A&D says “is generally expressed in output per excitation voltage (mV/V)”. Safe load limit is the load beyond rated capacity that causes no permanent damage. [1]

Manyyear's MLC400 compression load cell series, for example, lists 0.5 t to 1,200 t capacity, 1.0 or 2.0 mV/V rated output, 9–12 V DC excitation, 700 Ω input and output resistance and IP65 to IP68 versions. [2]

Editorial calculation: at 10 V excitation, a 2.0 mV/V cell gives 2.0 × 10 = 20 mV at rated load, and a 1.0 mV/V cell gives 10 mV. [2] Check that the amplifier or indicator resolves the force steps you need from that signal.

Give the supplier the force range, tension or compression, the mounting and load introduction, side loads, the required error, the temperature range, the signal or amplifier, and whether the force is static or dynamic.

02

Check error terms and temperature effects

A&D defines nonlinearity as the largest deviation from a straight line between zero and rated output on increasing load, hysteresis as the largest difference between increasing and decreasing load, and repeatability as the largest difference for the same load; it notes that OIML judges nonlinearity and hysteresis together against an error limit. Temperature effects on zero and on rated output are drifts with ambient temperature, and the compensated range is where the specifications apply. [1]

The MLC400 series lists 0.05–0.1% FS nonlinearity and hysteresis, 0.03–0.1% FS repeatability, creep of 0.03–0.1% FS over 10 minutes, a −10 to +40 °C compensated range and 0.05% FS per 10 °C temperature effect on both zero and span. [2]

Editorial calculation: a 30 °C swing with 0.05% FS/10 °C on zero gives 3 × 0.05 = 0.15% FS of zero drift; on a 10 t cell that is about 15 kg. [2] Re-zeroing before each measurement, or a cell with a lower coefficient, reduces this.

For fast force, Brans lists a piezoelectric tension and compression sensor from 1 to 60 kN with 2–3.5 pC/N output, natural frequency above 10 kHz, and nonlinearity, hysteresis and repeatability each of 1% FS or less; it describes this for dynamic and fatigue testing. [3]

03

Compare what suppliers offer

Suppliers linked to this page list load cells, force sensors and multi-axis force/torque sensors. [4] [2]

GALOCE lists miniature, force-washer, tension-compression, rope-tension, load-pin and three- and six-axis force sensors, and a spoke-type GSS406 cell rated 5–2,000 kN with 2.0 ± 0.2 mV/V and IP65; Manyyear lists button, tension and compression force cells; Brans lists column, donut, pancake and piezoelectric sensors; HAIBO, Labirinth, Mavin, Zhihe and Zhimin list beam, S-type, button and column load cells; Heli, Chengzhou and Hanwei list six-axis force/torque sensors; Zero Instrument lists strain-gauge and piezoelectric force sensors. [4] [2] [3]

04

Trace the sensor components

This is a functional reference built from the sources cited; it is not one maker's parts list.

05

Fill the specification fields with values for your application

A force sensor quotation needs values for your force and system. The table explains each field, gives published values where a reviewed source states them, and says what to obtain from the supplier.

06

Send the force, mounting and signal data together

Paste it into your enquiry below or into an email to a maker, then replace every bracket.

Force: [range; tension, compression or both; static or dynamic; frequency]
Mounting: [form; threads or pressure head; side and off-centre loads]
Accuracy: [combined error; nonlinearity; hysteresis; creep]
Environment: [temperature swing; IP rating; washdown]
Signal: [mV/V or amplified output; excitation; amplifier or indicator]
Documents: [calibration certificate; datasheet; drawing]

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