Chapter 16

Quality assurance

Quality standards

The use of automatic test software can greatly affect the quality of tests performed in calibration and/or test laboratory. Depending on the software, the tests can be affected either in a positive and a negative way.

On one hand, good quality software can reduce the risks of human errors and increase the quality of work/tests performed. On the other hand, is the software contains errors (and no software validation has been performed), it is very likely that the measurements performed will be incorrect, reducing the quality of the tests performed.

Several documents describe the need for software validation (or, as some documents describe it, first time verification). Both ISO17025 and ISO/IEC Guide 25 recognize the need for software validation. However neither document describe how this software validation should be performed. The document EA/GA(98)95 (version 4, May 1998) “Guidelines for the use of computers and computer systems in accredited laboratories” does describe guidelines for software validation. However this document is currently considered to be ‘informative only’.

DARE!! Instruments recognize the importance of software validation and has implemented special functionalities into the RadiMation^® EMC software package for this purpose. These functionalities make it possible to verify the performance of the test system as a whole and to reproduce specific tests at a later moment.

In addition to the first software verification, every new version of RadiMation^® undergoes a software verification specified by a pre-defined test plan. This eliminates the need for test houses to perform a complete software validation process.

The use of the RadiMation^® software (by the test houses) also influences the measurement quality and data security of the performed measurements. Because of this we strongly recommend test houses to adhere to the following advice:

1. Make back up files of the measurements results.
2. Install the RadiMation^® Software on a local test computer and use a network drive location for the data storage. This network drive can be automatically backed up. (Alternatively, the measurement data can also be stored on a test computer. However, be advised that in this situation special attention should be paid to backing up the measurement data on a regular basis.)
3. Set up access protection for both the computer system and the RadiMation^® Software package.
4. Appoint one or more individuals to be responsible for the configuration of the RadiMation^® Software (i.e. equipment configuration, TSF file configurations, setting default directories, entering correction and calibration files and appointing new test engineers).

To make sure that the RadiMation^® Software is in compliance with ISO17025, ISO/IEC Guide 25 and relevant parts of EA/GA(98)95, several measures have been taken. An overview of these is listed below under 'RadiMation^® Quality Issues'.

RadiMation^® Quality issues

General measures

1. The RadiMation^® Software package stores all test data, but does not have a possibility to change measurement data on a later moment, eliminating the possibility to temper with test results. On the other side it is possible to view test results at any time or to append new test data to an EUT file.
2. Test data of old versions of RadiMation^® can be viewed by newer versions, giving excess to old test data at any time.

Storage of all relevant data

All information that is relevant for the reproduction of the test(s) is stored. Below a summary is given of items that are recorded during a test:

1. All “RAW” measurement date is stored for later evaluation (i.e. all power meter(s), field sensor(s), receiver(s), A/D converter(s) readings etc. and signal generator settings).
2. All user configurable settings are stored with the measurement data (T.S.F. file settings).
3. All correction and calibration files used during the test are copied and stored with the test results.
4. All test equipment used during the test is stored (Equipment list).
5. Date, time and test engineer name are stored with the measurement data.
6. Error messages, which occurred during the test, are stored with the measurement results.

System verification prior to each test

While an EMC test set-up consists of a number of different test apparatus, one or more computers and one or more software packages, it is necessary to perform an overall system verification on a regular basis.

For this purpose, RadiMation^® makes a number of hardware, software and system verifications at the beginning of each test.

Radiated and conducted immunity tests

1. Prior to each test, the software will perform a power delivery test. During this power delivery test, the software increases the output power of the signal generator and measures the output power of the amplifier with the (forward) power meter. If the software measures a stable reading on the power meter, one can assume all cables are connected between the signal generator, amplifier, coupler and the power meter.
2. Prior to each test, the software will perform a linearity check. The software generates a stable signal generater output power, measures it on the power meter and then increases the signal generator level with 4 dB steps. If the power meter reading also increases with 4 dB steps, we can assume the amplifier is linear.

Radiated and conducted emission tests

Equipment verification prior to each test:

1. Prior to each test the RadiMation^® Software will check if all required test equipment can be found. If one or more apparatus are not found the software will stop with an error message.
2. Prior to each test the RadiMation^® Software will check if communication is possible with all required test equipment (initialisation). If one or more apparatus do not respond correctly, the software will stop with an error message.

Software settings verification prior to each test

1. Prior to each test the RadiMation^® Software will check if all user configurable settings of the Technical Set-up File (TSF file) are within the limits of the selected test equipment in the equipment list (i.e. does the antenna cover the required frequency range etc).
2. If a test is started which makes use of a calibration file, the software will verify if the currently selected test equipment (in the equipment list) was the same equipment as used during the calibration. For the sake of accuracy this is recommended. If different equipment was used, the software will warn for this and ask the operator to continue anyway, or stop the test.