Abstract. The aim of this submission is to introduc

J Hallon

R Bielik

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MEASUREMENT SCIENCE REVIEW, Volume 5, Section 3, 2005 
78 
Program system for controlling EMC measurements and collecting 
measured data 
R. Bielik, J. Hallon 
Department of Measurement, Faculty of Electrical Engineering and Information 
Technologies, Slovak Technical University, Ilkovicova 3, 812 19, Bratislava 
Email: roman.bielik@pobox.sk 
      j.hallon@kmer.elf.stuba.sk 
 
Abstract. The aim of this submission is to introduce a wide program system assigned to 
control EMC measurement. This device was developed on the Department of Measurement 
and can be divided into three modules. First component realizes defined supply voltage fails. 
The core of listed module is the programmable generator. The next component presents 
remote client for collecting, math processing and measured data evaluation from various 
EMC measurements. It works thought a serial interface and offers an option to simultaneous 
watch the three different channels for data collecting and one for parameters sending. A 
client for collecting, displaying and evaluation of received data constitutes the last 
component. The intention of this client is a measurement of higher harmonic frequencies. 
Additional optional functions of this module are the application of norm defined filtering and 
comparing measured data with norm defined limit values. 
Keywords: EMC, harmonic analysis, measurement software, GPIB 
1. Introduction 
The huge expansion of electrical devices and the increase of electromagnetic interfering 
signals bring the necessity to make devices resistant to these disturbances. In regard of 
legislation every electrical device has to satisfy to electromagnetic compatibility standards 
about emission of interfering signals and immunity to such signals. To achieve a valid 
certificate it is necessary to realize several extensive tests, with the use of various testing and 
measuring devices. In most cases it is important to use such measuring equipments, which by 
themselves won’t be the source of further interference and won’t have negative affect on 
object of measurement. In the simple way electromagnetic compatibility is the ability of a 
device or system to work properly in its electromagnetic environment without creating 
unwilling emissions to other devices. It has to also resist to similar interference coming out of 
other environment. 
The target was to build up a huge solid software system for performing control and analyze 
tasks in EMC measurements. The project goes out of real needs of the EMC laboratory. The 
project can be divided into three parts and matching software modules. 
2. Subject and Methods 
The specification of wished features was built up primary on the standards for Testing and 
Measurement Techniques (EN 61000-4-1) and Limits for Emission of Harmonic Current 
Emissions (EN 61000-3-2). There was also a request to use the whole potential, which is 
given to us by the measurement devices. 
There was a fundament question for the module for controlling immunity tests, what would 
be the best way of creation noise signal by using the HP33120A generator. Basically there 
were two different accesses. The first one uses by creating noise signals built-in functions of 
MEASUREMENT SCIENCE REVIEW, Volume 5, Section 3, 2005 
79 
the generator. But the trouble is, that it is not possible to change the output state (in meaning: 
starting or switching noise signal) with milliseconds precision. In spite of that, these built-in 
functions could be used in long lasting signals. The second access uses internal memory of 
the generator to achieve the samples of own built signals. In this case it is possible to build 
signals with precise dropouts, but there is also a restriction. The maximum number of samples 
is 16000 and the signal repeats cyclic with defined frequency. This is enough for only a 3 
second signal pattern with 50Hz frequency and density 100 samples per a period. 
In case of the remote interface for EMC tests, the focus was to build a two way 
communication application. The first channel should communicate with a server application, 
which controls the generator with antenna and tell it the frequency steps. The second channel 
should be used to get the measured data into the computer. There was a necessity to achieve 
the compatibility with other existing components such as the server application. 
The specific of the harmonic analysis module is, that it has strictly to work in real time and 
should be able to collect huge amount of data without lost five times per second. This module 
is also linked with a hardware device, which realizes the Fast Fourier Transformation (FFT) 
on the input signal. The need was to read this raw data from the HW device into computer and 
realize filtering and screening in the real time. The nearer features came out from the 
standards EN 61000-3. 
3. Results 
This paragraph describes the success of the project and every module. For better imagination 
several figures and graphs are present too. 
Module for controlling immunity tests 
The module uses the arbitrary waveform generator HP33120A to make noise signals and 
communicates with it through the GPIB bus. The basic signal presents a supply voltage, 
default set to 230V and 50Hz. However the output amplitude of the generator HP33120A is a 
hundred times smaller. The software module allows building up several types of noise signals 
listed bellow: 
• Short voltage dropouts with defined phase and delay in milliseconds. 
• Long lasting undervoltage/overvoltage. 
• Linear changes of the supply voltage amplitude (lasting seconds till tens of seconds). 
• Higher harmonic frequencies. 
• Frequency shifts. 
The noise signals are generated by combination of predefined waveform functions and sample 
waveforms defined on the generator. On the figure 1 is a sample signal, which can be 
generated with this module. 
MEASUREMENT SCIENCE REVIEW, Volume 5, Section 3, 2005 
80 
 
Fig. 1. Voltage signal with the defined short voltage dropouts. 
Remote interface for EMC tests 
This module is able to control the high frequency generator with the antenna in the shielded 
room. This is made by the communication with an existing server application through 
TCP/IP. The module simply connects to the server and sends appropriate commands to it. The 
results are several physical values, which describe the state of the tested device, which is 
exposed to the noise signal from the antenna. These physical values are transformed into an 
optical serial signal to minimize other interference. This data is then received with the module 
for collecting measured data trough RS232. Other features enable the math regress of the raw 
data, real time screening in a graph and archiving in a file. It is also possible to achieve three 
different input channels in the same time. 
The next figure 2 shows the main application window with a graph section. 
 
Fig. 2. Remote interface for EMC Tests application window. There is active a status page used to plot graph 
during measurement. 
Harmonic analysis module 
The last module presents a computer application, which communicates with a hardware 
device realizing Fast Fourier Transformation. This is performed through USB to reach a high 
data transfer speed. The raw data are then filtered with a first grade discreet filter as defined 
in the standard EN 61000-3. It is certainly possible to change the filtering properties. In the 
next step, these data are archived in the computer memory. In the last step, the data are 
screened in a bar graph. 
This all happens in a real time five times per second for every fifty higher harmonic 
frequencies. The additional features enable to compare measured data with norm-defined 
limits and to show direct value of selected frequencies. 
MEASUREMENT SCIENCE REVIEW, Volume 5, Section 3, 2005 
81 
The figure 3 bellow shows the main application window with a bar graph of a sample 
measurement. 
 
Fig. 3. Higher harmonic frequency module 
4. Conclusions 
The requirements of this program system have been reached and a full functional software 
package for controlling EMC measurements and collecting data has been made. 
The module for controlling immunity tests has some known issues, which relate with the 
limitations of the arbitrary waveform generator HP33120A. Before putting in operation is also 
a power amplifier required. Collector module for gathering measured data is already installed 
in the EMC laboratory and is often used in practice in many measurements. And the last 
module for collecting harmonic analysis data is full prepared for installing in the practice. 
References 
[1] Hudzovič,P.: Identification and modelling, ES STU, Bratislava 1986. 
[2] Agilent Technologies, Inc.: Agilent 33120A User guide (e-book), March 2002. 
[3] Szolik, I., Kováč, K., Smieško, V.: Influence of Digital Signal Processing on Precision of 
Power Quality Parameters Measurement. Proc. In: 4th Internation Conference 
Measurement 2003, Smolenice. 
[4] Kovács T.: Graduation theses, KMER FEI STU, Bratislava 2000. 
[5] Slovak Institute of Technical Normalization: STN EN 61000-3-2, Electromagnetic 
Compatibility. Part 3-2. Limits. Limits for Emission of Harmonic Current Emissions, 
Bratislava 2002. 
[6] Slovak Institute of  Technical Normalization: STN EN 61000-4-1, Electromagnetic 
Compatibility. Part 4-1. Testing and Measurement Techniques. Overview of Immunity 
Tests, Bratislava 2002. 


Program system for controlling EMC measurements and collecting measured data

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Program system for controlling EMC measurements and collecting measured data

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