Force calibration in tension and compression

Why calibrate force measuring instruments?

A force measuring instrument can drift without anyone noticing. Use, an overload, shocks, temperature changes and ageing of the strain gauges or the electronics shift the reading, without the display showing any sign of it. You only notice when a pressing process goes out of step, a lifting device turns out to be loaded more heavily than expected, or a tensile test in the laboratory gives different values from those at your customer's.

With periodic calibration you establish how large the deviation is and how reliable the measurement still is. Quality systems such as ISO 9001, customer audits and safety inspections therefore require demonstrably calibrated measuring instruments, with a certificate that is traceable to recognised references. If you know how far a transducer deviates, you can correct, adjust or replace it in time.

Measuring range and reference transducers

We calibrate by comparing your instrument with a calibrated reference force transducer (transfer standard) in the same line of force. For each calibration we select the reference that best matches the range of your instrument, so that the measurement uncertainty remains as small as possible.

Test and force calibration benches in the MASSLAB force laboratory

Reference	Equivalent to	Tension	Compression
10 kN	approx. 1,019 kg (1.0 t)	yes	yes
50 kN	approx. 5,095 kg (5.1 t)	yes	yes
100 kN	approx. 10,191 kg (10.2 t)	yes	yes
500 kN	approx. 50,953 kg (51.0 t)	yes	yes
4,000 kN	approx. 407,625 kg (407.6 t)	–	yes

Force is converted to mass using the local gravitational acceleration g = 9.8129296 m/s². We report results in N, kN, kg or t, as you prefer.

Standards and procedure

We work according to the standards and guidelines that are common in force measurement:

ISO 376 describes the calibration of force measuring instruments used to verify tensile and compression testing machines, including their classification. Read more at ISO 376 calibration.
ISO 7500-1 covers the calibration and verification of the force measuring system of uniaxial tensile and compression testing machines. We calibrate the reference instruments needed for this.
EURAMET cg-4 is the European guideline for determining measurement uncertainty in force measurements. We use it to calculate the uncertainty stated on your certificate.

Your instrument is loaded in increasing and decreasing load steps. This shows us not only the deviation at each measuring point, but also the hysteresis between loading and unloading and, with repeated series, the repeatability. In an ISO 376 calibration we also measure in several mounting positions, so that the reproducibility is known as well. All these contributions come together in the measurement uncertainty on the certificate. Not every calibration is automatically an ISO 376 calibration: for a force transducer from a press or a dynamometer from lifting equipment, a calibration of the complete measuring chain in the direction in which you measure is usually sufficient.

What can we calibrate for you?

We calibrate independently of brand, including instruments you did not buy from us:

Calibrating a crane scale in the tensile test bench at MASSLAB

Force transducers and load cells

Tension, compression and S-type transducers, ring transducers and load cells from machines, presses and weighing and dosing systems. In tension, compression or both.

Dynamometers and force gauges

Digital and analogue (tension) force gauges, hand-held dynamometers and reference force gauges from test laboratories.

Load shackles and load pins

Load-measuring shackles and pins from lifting, mooring and offshore applications, in tension up to 500 kN.

Hydraulic jacks and cylinders

Calibration of the force reading of jacks, cylinders and presses, via pressure gauge or display, in compression up to 4,000 kN.

Reference instruments for testing machines

Reference force transducers and measuring chains used to verify materials testing machines, according to ISO 376.

Crane and hanging scales

We check heavy crane scales on the tensile test bench up to approx. 51 t, with the reading in kg or tonnes.

Tailored calibration

No two applications are the same. That is why we tailor the calibration to how you use the instrument:

The complete measuring chain. We prefer to calibrate the transducer together with the indicator or amplifier you use it with. The result then applies to the combination you actually use in practice.
Number of measuring points. From a quick check with 3 load steps to an extensive calibration with 8 or more steps across the full range.
Direction. Tension only, compression only, or both directions in a single calibration.
Unit. Results in N, kN, kg or t, so that you can compare them directly with your own reading.
Class. For an ISO 376 calibration we classify your transducer according to the measured properties and the measurement uncertainty. We advise you on which class you need for your application.

How it works

You arrange the calibration online or with a single phone call; we take care of the rest.

1

Scheduling

Schedule the calibration via the customer portal or request a quote below. Let us know the type of instrument, the measuring range, the direction and the unit you require.
2

Collection and inspection

We collect your instrument. On receipt at our Elspeet facility we check it for damage and confirm that it is functioning properly.
3

Measurement

In increasing and decreasing load steps we compare your instrument with our reference transducer, in tension and/or compression. If it deviates too much and adjustment is possible, we consult you first.
4

Certificate and return

You receive a digital calibration certificate and your instrument is normally back with you within 10 working days. In a hurry? A faster turnaround is possible by arrangement.

What does the certificate contain?

all measuring points, in the unit you have chosen;
the deviation at each measuring point and the measurement uncertainty, calculated according to EURAMET cg-4;
the reference transducer used, its traceability and the ambient conditions during the measurement;
where applicable, the classification according to ISO 376;
after adjustment, the results before and after adjustment;
a recommendation on the calibration interval.

The certificate is also available in the customer portal. There you can see the history of each instrument and when the next calibration is due; we send you a reminder in good time. MASSLAB is a Recognised Verifier (Erkend Keurder) under the Dutch Metrology Act. Calibrations are performed according to internally established procedures based on the relevant requirements of ISO/IEC 17025. Where applicable, measurement results are stated with measurement uncertainty and supported by traceable measurement references. If a certificate under accreditation is mandatory for you, please discuss this with us in advance.

Who is it for?

Force measurements play a role in many sectors. We calibrate, among others, for companies in lifting and hoisting and offshore and maritime, where load shackles and dynamometers determine whether a load is lifted safely. In construction and civil engineering it concerns jacks, cylinders and compression transducers used in prestressing and load testing. The manufacturing industry and machine building use force transducers in presses and assembly lines, and weighing and dosing technology relies on load cells in silos and dosing systems. Test and inspection laboratories need reference transducers to verify their tensile and compression testing machines.

Do you weigh with a crane scale or load cell in kg or tonnes? Then force and weighing are closely related. Read also how we calibrate scales and what the difference is between mass, weight and force.

Build your quote

Select the instrument, the direction and the measuring range and add the calibration to your quote basket. You can combine several instruments, including weights from our webshop. Details such as brand, type and required class can be entered when you submit your request.

Instrument Direction Measuring range (maximum force) Quantity

Go to quote basket

Price on request · state make, type and requirements (display, number of steps, class) in the remarks of your request.

Which instrument would you like to have calibrated?

Force transducer and load cell

Force transducer or load cell calibration in tension and compression, with or without display. 3 to 8 or more load steps, traceable certificate with uncertainty.

Dynamometer and force gauge

Have your dynamometer or force gauge calibrated in tension or compression up to 500 kN. Results in N, kN, kg or t, with traceable certificate and reminder service.

Load shackle and load pin

Load shackle and load pin calibration in tension up to 500 kN, including display or indicator. Traceable certificate with all measuring points and uncertainty.

Hydraulic jack and cylinder

Hydraulic jack and cylinder calibration in compression up to 4,000 kN, against a calibrated reference force transducer. Traceable certificate with uncertainty.

ISO 376 calibration

ISO 376 calibration of reference force transducers and measuring chains for verifying tensile and compression testing machines to ISO 7500-1. Traceable certificate.

Frequently asked questions

How often should I have a force measuring instrument calibrated?

We recommend starting with an interval of 12 months, or shorter in the case of intensive use. If successive calibrations show that the instrument is stable, you can extend the interval on a substantiated basis. ISO 376 allows a maximum of 26 months for reference transducers; tensile and compression testing machines according to ISO 7500-1 are generally checked annually. After an overload, a fall or a repair, immediate recalibration is advisable.

What is the difference between calibration, adjustment and legal verification?

Calibration establishes how much an instrument deviates from the reference. Adjustment means correcting the instrument so that this deviation becomes smaller; we then measure again. Legal verification is a statutory inspection, for example for scales used in trade. Force transducers and dynamometers are generally not subject to legal verification, but your quality system will usually require them to be calibrated.

Which accuracy class do I need?

That depends on the application. According to ISO 376, a reference transducer used to verify a testing machine must be of at least the same class as the class in which the machine is classified. For industrial applications, class 1 or 2 is often sufficient. We are happy to advise you.

Do I need to send in the transducer together with its display?

Yes, we recommend this. We then calibrate the complete measuring chain as you use it, and the certificate applies to the combination of transducer and readout.

Where are the force calibrations carried out?

On our own hydraulic tensile and compression test benches at our Elspeet facility. We collect your instruments and return them, and you can follow the status and certificates in the customer portal.

Does MASSLAB work according to ISO/IEC 17025?

Calibrations are performed according to internally established procedures based on the relevant requirements of ISO/IEC 17025. Where applicable, measurement results are stated with measurement uncertainty and supported by traceable measurement references. If you need a certificate under accreditation, please discuss this with us in advance.