Overview

In modern metrology and testing software is involved in many devices and systems. First of all, software is integrated in measuring instruments (i.e. firmware of instruments or workstation–based instruments, stand-alone or networked systems) and in on-line used laboratory automation systems for measurement and calibration (i.e. data acquisition, instrument control and communication, curve fitting). Another group of applications is related to the management of measurements, e.g. laboratory information management systems (LIMS), document management systems and access control. Finally, there are applications that analyse measurement results (statistical analysis, uncertainty estimation), model measuring processes, and support metrological databases, etc. 

Future development

The development of technology is extremely rapid. In the near future, the readout, calibration or, for example, parameter setting of measuring instruments will be done by smartcards via local computer networks (e.g. at filling stations), via a GSM modem (contemporary electricity meters), via mobile communication networks or over the private or even public network (Internet). Updating of software will be made through automatic download of software. All participants in transactions as well as the data will have to be identified and protected through electronic signatures (i.e. public key infrastructure). In addition to the software running on the computer of the measuring instrument computer, communications and databases are implemented to enable distributed measuring systems, measuring data storage and their subsequent processing.

This progress is undoubtedly useful for the users, because it enables faster measurements, higher accuracy and opens up the possibility of various analyses and further processing. Legal metrology, however, is facing numerous problems because of wanting on the one hand to facilitate the use of modern technologies for manufacturers and users and on the other hand, improvements in technology render consumer protection a more demanding task.

The WP4 "Future aspects"  of the EU 5th FW Project MID-SOFTWARE identified following aspects as necessary for immediate further investigation:

- remote meter operation via various private or even public communication networks (internet, cable-TV network, power supply, mobile communication, ...) - remote readout, identification and authentication of participants in data exchange, key infrastructure, software download, remote configuration and inspection, data security, integrity aspects, …

- use of SMARTCARDs in legal metrology applications - readout, identification and authentication of participants in data exchange, key infrastructure, software download, configuration and inspection, data security, integrity aspects …

- multi-purpose measuring instruments and intelligent sensors.

As Mr. Sandro Minuti from Gilbarco said during his presentation on the FASIT workshop, the sequence of legal measuring instruments development phases starts with “iron age”, continues with “electronic age” followed by the “software age” and nowadays we are already in “communication age”.

Development of legal measuring instruments is going in direction of (or already is) distributed (networked) measuring systems, which will:

- add additional functionality and flexibility in operation of measuring instruments (remote tariff or unit price change for taximeter, fuel dispenser or balance, readout of utility meters, calibration, software update via download and other maintenance, …);

- cause that measuring instrument will actually be physically distributed among several locations;

- use centralised databases in measuring systems for measurement data collection for issuing the invoices and some other functions (tariff calculation, maintenance, …);

- have additional functions attached to measuring instrument or system components  that will require careful software separation (inventory management, i.e.);

- require high – level skills for tampering;

- require much higher level skills for tampering detection and surveillance.

Examination (verification and validation) of metrological software

A software module in a measuring instrument is suitable if it calculates the values of the output parameter O for a given value of the input parameter I. During testing, one may observe the numerical correctness of the calculation result, taking into consideration the limitations of the implemented algorithm, the technology of the software (type of variable, rounding, etc.) and the software environment.

A reliable program will give the result O(I) every time, regardless of the load of the host computer, transmission lines, etc. Legal metrology has additional requirements: software in legal metrology instruments is not allowed to implement undocumented functions and needs to have sufficient protection of the program code and parameters that are kept in the computer’s memory storage or transmitted via communication lines.

The requirements for the quality of metrological software may be regarded from several expert points of view, like software technology standards, legislation, safety-related standards, laboratory competence standards, or as the combination of them.

Guidance documents

Parties involved in the field of metrological software are interested in getting a clear guidance for software quality requirements and validation methods. These parties are laboratory staff, metrology experts, accreditation bodies, manufacturers of measuring instruments and systems, IT specialists, legal metrology and other inspection bodies, and, of course, end users of metrological services.

With the intention to support the quality evaluation of the metrological software, several guidance documents have already been generated, such as the WELMEC guides (2.3, 2.5, 7.1, 7.2), the OIML D-SW draft guide, the EEEE* draft guide, the NORDTEST software validation guide, the Canadian “Specification Relating to Metrological Software”, and the FDA guides.

Some guides include requirements only, others address validation as well. Another aspect is whether the guide addresses validation of software as a final product or gives additional software verification and development guidance. In some guides the strength of requirements and the thoroughness of validation are derived from consequent risk assessments for software malfunction or fraud.

Databases in metrology

Metrological databases are used in various metrological fields, for example:

- Research area: storing the measuring results for later analysis and improvement of medical diagnostic

- Validation of tools and procedures:

     ▪ Reference software for validation of self-developed standardised software modules

     ▪ Reference software for validation of self-developed basic mathematical software modules

     ▪ Reference datasets for software validation

- Legal metrology: storing the measuring results for dynamical tariff calculation (i.e. meters of electrical energy

- Management of a distributed metrology system.

MIRS department for Information Technology in Metrology is currently running a project of establishing the system of databases for supporting co-ordination of processes under responsibility of the Metrology Institute of the Republic of Slovenia.

Intersting links

Fasit: http://www.mirs.si/fasit

Selma: http://www.selma-project.de

Ssfm: http://www.npl.co.uk/ssfm/

NIST http://csrc.nist.gov/, http://www.nist.gov/srd/

FDA: http://www.fda.gov

PTB: http://www.softwarepruefstelle.de/

*) Eurolab, Euromet, Eurachem and EA ad-hoc working group for preparation of Guidelines for the use of computers and software in laboratories with reference to ISO 17025