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.
On one hand, if the software is correct, the quality of the work done can increase because human errors are reduced. On the other hand, if the software contains errors and no software validation has been performed, it is very likely that the measurements performed will be incorrect and thus the quality of tests performed will reduce.
Several documents describe the need for software validation (or, as some documents describe it, first time verification). Both EN45001 and ISO/IEC Guide 25 recognise the need for software validation. However both documents do not go into the way to perform software validation. 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 at this moment, the document is informative only.
DARE!! Development has recognised the importance of software validation and has focussed on this subject during the development of the RadiMation® EMC software package. As you will notice, a lot of extra software functionality is added to the RadiMation® software package, just to verify the functionality of the test system as a whole and to make it possible to reproduce tests performed at a later moment.
Apart from the first software verification, every new version of the RadiMation® Software undergoes software verification according to a pre- defined test plan, eliminating the need for test houses to perform a complete software validation process.
Of course, each test house should take care of the following points:
- Back up’s of the measurements results.
- For the sake of data security, we recommend to install the RadiMation® Software at a local test computer and use a network drive location for the data storage (this network drive can be automatically backed up). Of course, the measurement data can also be stored on a test computer. However, in this situation extra attention should be paid to backup the measurement data on a regular basis.
- Access protection of both the computer system itself as the RadiMation® Software package.
- Appointing one or more persons who are 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 achieve software which is in compliance to EN45001 and ISO/IEC Guide 25 and relevant parts of EA/GA(98)95 several measures were taken. The list below is an overview of all measures taken:
1. General issues 2. Storage of all relevant data 3. System verification prior to each test 4. Equipment verification prior to each test 5. Software settings verification prior to each test
16.2 RadiMation Quality issues
16.2.1 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.
16.2.2 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.
16.2.3 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.
16.2.4 Radiated and conducted immunity tests
1. Prior to each test the software will perform a power delivery test. During this test, the software increases the output power of the signal generator and measures the output power of the amplifier with the 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 and power meter. 2. Prior to each test the software will perform a linearity check. The software generates a stable output power, measured on the power meter and then increases the signal generator level by 4 dB. If the power meter reading also increases by 4 dB, we can assume the amplifier is linear. 3. If a field sensor is used during the tests (or a current sensor during conducted immunity tests), the software will perform a field (current) verification test. During this test the software will generate a power in accordance to the calibration file and check if the generated field is within 6 dB of the expected field.
16.2.5 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.
