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Communications Technology of Weighing Instruments

Working Group 1.14


Working group 1.14 „Communications Technology of Weighing Instruments“  works at the interface between
Opens internal link in current windowinformation technology and Opens internal link in current windowweighing technology. It is concerned with metrological software for weighing instruments, modules and peripheral devices. Existing and partialy superordinated regulations are interpreted and apllied but also developed further by work in the respective committees.
Besides work in the field of legal metrology, the woking group is engaged in research and development concerning weighing technology and beyond.

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Project "Ceraforce"

The Ceraforce project aims to examine a new sensor principle based on ceramic materials. Current high-resolution force measurement sensors for long-term applications show drift behavior, which is often caused by the creep of hardened metals used in these sensors. The sensor consists of a non conductive ceramic spring which is metal coated between the spring windings. If a force is applied the resulting winding displacement can be measured by means of a change in the capacitance between these two metal surfaces. Apart from applied fundamental research on the sensor properties the project focuses on the design and development of a novel relative gravimeter.

Project "LoBEK 3D"

Novel procedures for the inspection of 3D hole-patterns in Coordinate metrology with large measurement data sets


PTB together with an industrial manufacturer of coordinate measurement machines  investigates reliable methods for a computational simulation of product assembly by 3D hole-pattern fitting procedures. An example application is the inspection of flange rings for wind turbines. The research is founded by the Federal Ministry for Economic Affairs and Energy. It started in April 2015 and has a duration of 30 months. The aim is to have adequate methods at the end of the project that can keep up with the steadily increasing requirements for the evaluation of optical and CT measurement data. Moreover developers and users of 3D hole-pattern fitting will be enabled to quantify the precision of their software results for the first time. This will help to improve the quality of products in different industrial sectors such as automotive engineering , microelectronics and medical engineering in the long term.

Further informationen ...

Figure 1: Requirements at the assembly of a flange ring with bolts

Figure 1 shows the assembly of two flange rings. To mount both parts several bolts must fit in all drill holes at once. The drill holes are crooked due to inevitable manufacturing deviations. To see if all drill holes are within an acceptable tolerance of deviations, 3D hole-pattern fitting compares the flange with a geometrically ideal counterpart.

The research starts with dimensioning and tolerancing principles within the standards ISO 1101 and ISO 2692 which lead to inspections with assembly simulation. PTB offers a guide for an application of these methods for coordinate measuring machines according to the requirements from the before mentioned standards (Opens internal link in current windowdownload).

At present flange rings for wind turbines have diameters up to 5 meters with more than 50 drill holes. Thus software for 3D hole-pattern fitting has to work highly efficient, as measurement data sets for all holes can comprise many millions of measurement points. PTB developed a novel reference algorithm which is capable of accurate calculation of the fitting with considerably better performance than formerly used software.

In future parts of the project software tests will be implemented for different applications of 3D hole-pattern fitting. These comprise test data sets with an a priory known fitting solution and evaluation procedures for the comparison of different calculations results. The test will be offered to industry as new services via an online test system.

Project AWICal

The aim of the project is to develop a harmonized European method for the calibration of automatic weighing instruments. While for non-automatic weighing a guideline for calibration exists (Euramet guide CG-18) for many years, there is not something similar for automatic weighing instruments currently.
The AWICal project started in June 2015 and will be completed within 3 years. The project was initiated by the Slovenian National Metrology Institute MIRS. Beside PTB project partners are the Austrian National Metrology Institute BEV with the test office PTP, the National Metrology Institutes of Czech Republic (CMI), Poland (GUM), Bosnia and Herzegovina (IMBiH), Estonia (Metrosert), Serbia (MoE) and Turkey (TUBITAK). Furthermore the company of Mettler-Toledo participates as a manufacturer of automatic weighing instruments.

Three types of automatic weighing instruments will be examined: automatic checkweighers, automatic gravimetric filling instruments and automatic weighing instruments for weighing road vehicles in motion.

The project is divided in the following working fields:

  • Develop and validate calibration methods for the selected types of automatic weighing instruments
  • Determine influence quantities and possible errors for dynamic weighing
  • Develop and validate measurement uncertainty budgets
  • Develop drafts of calibration guides for the selected 3 types of automatic weighing instruments

To check the reproducibility of the developed measurement methods and to validate the uncertainty budget there will be comparisons between the measurements of the project partners.

Especially in the measurements PTB will bring in their experience in the testing of automatic weighing instruments

You can find further information on the project on its web page Opens external link in new windowwww.awical.eu.

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  • Consultations regarding software for weighing instruments, modules and peripheral device
  • Pre-assessment of software for weighing instruments and modules in order to facilitate a subsequent conformity assessment of the entire device

The services are offered within the scope of the PTB conformity assessment body
Opens internal link in current window(KBS, sector 2). On its web page you can find further information on conformity assessment procedures.

If you want to order a type examination, please use the Opens internal link in current windoworder form from the PTB conformity assessment body and send it to Opens window for sending emailwaagen(at)ptb.de.

The costs for testing and evaluation depend on the effort. The hourly rate is given in the Regulations Governing Charges for Services Supplied "Kostenverordnung fuer Nutzleistungen" Opens internal link in current window (KVONL).



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Regulations, standards and recommendations:

  • Measurement and verification law (Opens external link in new windowMessEG)
  • Measurement and verification ordinance (Opens external link in new windowMessEV)
  • European Directive 2014/31/EU (Opens external link in new windowNAWID)
  • European Measurement Instruments Directive(Opens external link in new windowMID)
  • OIML Recommendations (Opens external link in new windowOIML)
  • WELMEC Guides (Opens external link in new windowWELMEC)

Project LoBEK:

Interesting links:

  • Verification authorithies (Opens external link in new windowEichamt)
  • Working group metrology and verification (Opens external link in new windowAGME)
  • VDMA - department weighing technology (Opens external link in new windowVDMA)

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