Force measurement

The instrument that decides whether a test is true.

A load cell converts force into an electrical signal — a conversion that is indirect and happens in stages, which is why the device is properly called a precision electronic force measurement unit. It is the component that decides what a testing machine actually knows about the specimen in its grips.

Standard capacity

0.05 kN to 600 kN

Safe overload

150% of capacity

Protected to

At least 300% of rated capacity

Dak load cells are designed to meet or exceed the requirements of ASTM E-83, BS 3846, ISO 9513 and EN 10002-4, alongside the operating requirements of the Dak machine they are fitted to. Their function is to measure the force applied to the specimen precisely, and they work with any Dak readout or data acquisition system.

The range is built to cover a testing programme rather than a single test: capacities from 0.05 kN to 600 kN, in tension only, compression only, or both.

Construction

What is inside the housing, and why it matters

Six things that separate a load cell you can trust over years from one that merely reads a number today.

Strain gauges, bonded and sealed

Each cell is built from high-quality materials with strain gauges applied, permanently bonded and sealed. Force is measured in one of three configurations — tension only, compression only, or tension and compression together.

Two body types, by capacity

Below 20 kN the cells are S-type. At 20 kN and above they are Low Profile Universal — the pancake form — which is what allows a high-capacity cell to sit in the load train without adding height to it.

Overload protection as standard

Every cell is safe to 150% of its capacity and protected against at least 300% of its rated capacity without mechanical damage. Overload protection is automatic, not a setting somebody has to remember.

The cell identifies itself

Each cell carries non-changing coding memory in its connecting plug, holding its calibration and limit parameters. Fit a different cell and the system knows what has been fitted, along with everything it needs to read it correctly.

Calibration is entirely digital

There are no presets and no trim pots — the components a conventional cell relies on and the ones that drift. Calibration being digital is what removes the effect of voltage and temperature variation from the measurement.

Built for the measurement chain

Higher load accuracy and an increased data rate carry through to the console, where up to four transducer control channels can be integrated — so load, strain and a further two measurements are acquired together rather than in separate passes.

Below 20 kN

S-type

The S-beam form, used across the lower capacities where the load train has room for it.

20 kN and above

Low Profile Universal

The pancake form — a high-capacity cell that sits in the load train without adding height to it.

Accuracy

How far down the range the figure holds

Accuracy on a load cell is two numbers, not one: the error, and the fraction of capacity it still applies at. A cell that is accurate at full scale and vague at a tenth of it is no use for a programme that tests both.

Series 7200

±0.005% of full capacity

±0.5% down to 1/100th of capacity

Self-identification and digital auto-calibration.

Series 9000

0.02% of full capacity

±0.5% down to 1/100th of capacity

Self-identification and digital auto-calibration.

Load cell and pre-amplifier classes

Every class holds ±0.5% of reading. What separates them is how far down the cell’s capacity that figure continues to apply.

Class A

±0.5% of reading

down to 1/500 of capacity

Class B

±0.5% of reading

down to 1/250 of capacity

Class C

±0.5% of reading

down to 1/100 of capacity

Class D

±0.5% of reading

down to 1/1000 of capacity

Resolution

What each capacity actually reads to

Both units are given because a laboratory works in one or the other, and converting in your head at the specification stage is how the wrong cell gets ordered.

10 kg (100 N)

Display
10.0000 kg (100.000 N)
Resolution
0.1 g (0.001 N)

100 kg (1 kN)

Display
100.000 kg (1000.00 N)
Resolution
1 g (0.01 N)

500 kg (5 kN)

Display
500.000 kg (5000.00 N)
Resolution
1 g (0.01 N)

5000 kg (50 kN)

Display
5000.00 kg (50.0000 kN)
Resolution
10 g (0.1 N)

10 ton (100 kN)

Display
10000.0 kg (100.000 kN)
Resolution
0.1 kg (1 N)

20 ton (200 kN)

Display
20000.0 kg (200.000 kN)
Resolution
0.1 kg (1 N)

40 ton (400 kN)

Display
40000.0 kg (400.000 kN)
Resolution
0.1 kg (1 N)

Force verification

Meets or exceeds:

ASTM
ASTM E-4
ISO
ISO 7500/1
EN
EN 10002-2
BS
BS 1610
DIN
DIN 51221
JIS
JIS B7721

Strain measurement

Strain measurement accuracy of ±0.5% of reading down to 1/100 of full scale conforms to ASTM E-83 class B, or ISO 9513 class 1 extensometer.

ASTM
ASTM E-83
ISO
ISO 9513
EN
EN 10002-4
BS
BS 3846

Not sure which capacity your programme needs, or whether one cell will cover it? Tell us the forces you expect and we will specify it.

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