Calibration of Electronic Test Equipment: An Introduction to ISO & Accreditation

Calibration of Electronic Test Equipment:

• What does “Calibration” mean?

• What is ISO 17025, what is Accreditation, and what is the

difference?

• What’s good and what’s not so good?

• What does Agilent Italy offer?

ISO-VIM-1993

International Vocabulary of Basic and General Terms in Metrology:

“Calibration: a set of operations that establish, under specified

conditions, the relationship between values of quantities indicated by a measuring instrument or measuring system, or values represented by a material measure or reference material, and the corresponding values realized by standards.”

Agilent Technologies / other vendors / Industry required:

“Calibration: comparing an instrument’s performance with respect to the original equipment manufacturer’s specifications and full traceability to the appropriate regional Authority. If it is needed, proper adjustments is done.”

ISO/IEC 17025:2005 is an international standard for

calibration and testing labs

Requires labs to demonstrate that they:

• Operate a quality system

– Processes, documentation and quality management system • Generate technically valid results

– Traceability, equipment, procedures, personnel etc...

It takes relevant parts of ISO 9001 and adds the former

ISO Guide 25 to form a standard that is focused on the

measurement industry

Who

does

use ISO 17025?

All national accreditation bodies have adopted ISO 17025

Several industries or countries have incorporated it into

their industry-specific or application-specific regulations

Some examples

– ISO9000: par. 4.11 (1994) par.7.6 (2000) via ISO10012 – QS-9000: quality standard for the automotive industry – AQAP Military Standards

Customers need to determine the relative quality and capability of different cal labs

• Customers can compare the measurement results from different vendors

• For multi-national companies, they can compare vendors in different countries

Customers gain a higher confidence level in the calibrations they purchase

International trade is increased by reducing potential quality barriers

A global standard to provide consistency

Why this Standard?

Vendors need to confirm their quality and competence

• Can conduct an internal audit through their own quality department • Can undergo an external audit from each of their major customers

Vendors can now schedule a single third-party audit and become accredited to a common set of requirements

A formal recognition process where an authoritative body

reviews and approves a calibration lab’s quality system

and technical competence

• Each country has its own accreditation body

– A2LA in U.S., UKAS in U.K., JCSS in Japan, SIT in Italy, etc.

• Mutual recognition via ILAC/EA agreements

• All accreditation bodies use ISO 17025

• ISO17025 does not replace ISO9000

International Standards

ISO Guide 25

ISO Guide 25

ISO/IEC 10012-1 & 2:1992

ISO/IEC 10012-1 & 2:1992

ISO/IEC 17025:1999

ISO/IEC 17025:1999

ISO/IEC 10012:2003

ISO/IEC 10012:2003

ISO 9000:1994

ISO 9000:1994

ISO/IEC 9000:2000

ISO/IEC 9000:2000

Quality Management System Requirements:

Technical Management System Requirements:

QS-9000-1994

QS-9000-1994

ISO/TS 16949:2002

ISO/TS 16949:2002

ISO/IEC 17025:2005

Specific

measurement parameters

are accredited

– Some small vendors are only accredited for few parameters such as DC & AC voltage, DC & AC current, resistance

– Some larger vendors are accredited for 15 or more parameters

Accredited parameters are documented in a public

document, the “scope of accreditation”

– Includes approved parameters, ranges, and best measurement capabilities

Comparing Requirements

ISO 17025 versus Accreditation

ISO 17025

ISO 17025 versus Accreditation

ISO 17025

Accreditation

Ideal Situation

ISO 17025 and Accreditation

requirements are identical

Typical Single Country Situation

ISO 17025 versus Accreditation

Accreditation

ISO 17025

Accreditation requirements are a super-set of

ISO 17025 requirements

Typical Single Country Situation

ISO 17025 versus Accreditation

Accreditation

Current Global Situation

ISO 17025 versus Accreditation

Accreditation

ISO 17025

Accreditation requirements (and sometimes how

ISO 17025 is interpreted) are slightly different

from country-to-country

Local differences

As suggested in:

– ISO17025:2005 par. 5.4.2 – ISO10012:2003 par. 6.2.1

it can be based on manufacturer performance test

procedure.

Validated Procedure

Is:

Point-by-point measurement uncertainty

– Per ISO Guide to the Expression of Uncertainty in Measurement

(GUM) or EA4/02 guide or UKAS M3003 etc.

– Measurement uncertainty must be provided for

all

Is not:

general table of “best measurement uncertainties”

Measurement Uncertainties

If a vendor states that the unit

complies with a specification, then

the measurement uncertainty must

be taken into account

– Specification can be “manufacturer specification” as suggested in

ISO10012:2003 par. 6.3.1 and 7.1.4 – To take into account uncertainty you

can follow ILAC-G8 guide or M3003 guide

– If adjustments are done, PRE & POST

“Statement of Compliance”

Validated Procedure

– Must be approved by local accreditation body

– Could be different of manufacturer recommended

Measurement Uncertainties

– Should be the same as the ISO 17025 calibration

– In Italy measurement uncertainty can be provided only for parameters/ranges in the “Scope of Accreditation”

State of Compliance

– Should be the same as the ISO 17025 calibration

– In Italy not applicable, only to specific standard. Under Accreditation, the “Calibration” definition is only the VIM

Country-specific requirements

Country-specific requirements

Accreditation requirements/differences

Often this means limited calibration compared with

manufacturer requirements for Complex M&TE

Confirm what level of compliance is required for your industry or country

• For example, QS-9000 or Military standards requirements are more rigorous

Ask yourself the following questions:

• Which kind of vendor do you need?

– Complies with ISO 17025, but may not meet all the requirements of the local accreditation body

– Accredited to ISO17025

• Which kind of calibration do you need? – Complies with ISO 17025

– Accredited to ISO17025.

o but, is the vendor accredited for all the parameters that your equipment requires? o Are the uncertainties corrects for your equipment requirements?

Four aspects that need to be considered...

A lab can sell a

17025-conformant (non-accredited) calibration service

need external

A lab can sell a

17025-conformant (non-accredited) calibration service

need external

A lab can sell a 17025 Accredited calibration

service

Check its ”scope of accreditation”

A lab can sell a 17025 Accredited calibration

service

Check its ”scope of accreditation”

A lab is 17025 accredited Assessed by an Accreditation body A lab is 17025 accredited Assessed by an Accreditation body

2

ISO 17025 & Accreditation Summary

• Internationally recognised • Intends to introduce

standardisation into the industry • Provides users with better quality

assurance

• Ideally suited to a laboratory

specialist who knows exactly what he wants

• Partial testing allowed • Still creates confusion

• Can give false sense of security • Not ideal for the person who

manages a large volume/range of equipment

• Not so focused on measurement industries requirements

What does Agilent Italy offer?

Service Center in Italy

• Centro SIT n.05 - In 1979 Agilent’s metrological standard laboratory was the first one to be accredited by SIT for electronic quantities

• Quality System registered to ISO9001:2000

• Technical System accredited to ISO17025:2005

Accredited Laboratory Centro SIT 05

AgilentLab A Lab B Lab C Lab D Lab E Lab F Worst Case

Power Sensor CF Calibration 1 mW-1 GHz

3E-13

7E-12 1E-117E-12

2E-123E-12 7E-12 3E-11 0E+00 5E-12 1E-11 2E-11 2E-11 3E-11 3E-11 Un ce rt ai nt y

AgilentLab ALab B Lab CLab DLab ELab FWorst Case

Reference Oscillator Calibration Fequency 10MHz

• Accredited quantities: DC Voltage, DC Current, DC Resistance, AC Voltage, AC Current, AC Resistance, Capacitance, Inductance, Attenuation, Frequency, Reflection Coefficient, RF Power (& Cal Factor)

• Coming soon: Optical Power, Optical Attenuation, Optical Wavelenght • Best uncertainties on the market • Since 1992 has successfully

partecipated to more than 20 ILC national (SIT/INRIM) and

international (EA/ILAC)

Agilent ISO 17025 Conformant Calibration

Applicable to Agilent Complex M&TE, i.e. Spectrum, Network, RF & MW Generator, Mobile Test-set etc...

• Supported list on the Web.

Validated Procedure

• Full parameters following Manufacturer Procedures

Measurement Uncertainty

• All measurements following ISO GUM

Traceability

• Guaranteed by Centro SIT 05, others Accredited Agilent Labs or NMIs.

B, C = “PASS #”. Performance falls within the measurement uncertainty on the ‘in-spec’ side.

A = “PASS”.

A statement of specification compliance is issued. B and C are not adjusted to be closer to centre.

D, E = “FAIL”. D’s Performance falls within measurement uncertainty on the ‘out-of-spec’ side and is considered a FAIL E is totally out-of-spec with and without uncertainty

Agilent’s treatment of the ‘indeterminate’ situation

This pragmatic approach has met with general approval from users

Measured values Measured values

The customer is notified on the measurement report that: “All measured values indicated by this data report lie

within specification. Due to measurement uncertainty, the true values of one or more of these points may lie outside of the specification, but there is a high probability that these values lie within specification.”

For more information

Agilent Metrology Forum

http://www.agilent.com/metrology

• General information on calibration and standards

• List of Agilent service centers/standards labs and their accredited parameters

• Calibration myths, metrology humor, and other articles of interest

http://www.agilent.com/metrology/sit_schedule.shtml

• Information on the Centro SIT 05 and on the Calibration and Repair Service Center in Italy