One-shot Results for Narrowband, Full Spectrum and Harmonics
|Memory and Interfaces||
|LMG640 (Table top)||284 mm||177 mm||590 mm|
|LMG640 (Rack)||55 HP||4 RU||590 mm|
|Weight||Depending on installed options: max. 14.0 kg|
|Protection class||EN 61010 (IEC 61010, VDE 0411), protection class I / IP20 in accordance with EN 60529|
|Electromagnetic compatibility||EN 61326|
|Temperature||0 ... 40 °C (operation) / -20 ... 50 °C (storage)|
|Climatic category||Normal environmental conditions according to EN 61010|
|Line input||100 ... 230 V, 47 ... 63 Hz, max. 400 W|
In Power meters of traditional construction, a signal first passes through an analog processing, the output values are digitized by an A / D converter and then processed. The resulting signal may then either measured over the full range, or treated with anti-aliasing filters, e.g., to serve as the basis for an FFT or other digital filtering. By restriction to an A / D converter, one has to taken certain disadvantages into account. If measured with a filter, in order to avoid aliasing in the FFT, the broadband values are lost. When the filter is disengaged, strictly speaking, the FFT has to be omitted. If the FFT is performed without anti-aliasing filter for measurement over the full bandwidth, the quality of the calculated values is questionable. For example, an aliasing error of 50% would of course be easily detected, a deviation of 0.5% could remain unnoticed. Finally, it can be switched back and forth between measurements with and without filters. The validity of these results is, however, also doubtful, as would be expected of a temporal invariability of the signal, which is hardly ever the case in reality. Moreover, this method is extremely time consuming.
Ultimately, the shown measurement methods are unsatisfactory compromises. For this reason, ZES ZIMMER has radically redesigned the signal conditioning and developed the DualPath architecture. The analog side corresponds to the conventional instruments, the subsequent digital processing, however, was revolutionized. The power analyzers of the LMG600 Series are the first power meters featuring two A / D converters in each of the two independent signal paths for current and voltage channel. A filter for the contact measurement of the broadband signal, and another for the narrowband signal at the output of anti-aliasing filter. By means of parallel processing of the digitized samples, the user has access to both measurements of the same signal without the risk of aliasing. This unique process eliminates all the disadvantages of previous approaches and guarantees accurate results in the shortest time.
In an effort to reduce energy consumption, light bulbs are replaced worldwide with more efficient electric lamps. While to the consumer it is just a new product in an old socket, the differences in electrical terms are considerable - in contrast to conventional light bulbs, LED lights and compact fluorescent lamps ("energy saving lamps") are controlled by special electronic ballasts. These ballasts operate in part with switching frequencies up to 200 kHz and generate signal distortions at frequencies up to 1 MHz. The manufacturers are required to prevent detrimental circuit feedback and to ensure optimum service life of their products. To achieve the latter goal, a controlled warm start is often performed, which proper implementation in turn must be ensured by measurements.
Advances in power electronics have lead to a shift from relatively large and heavy transformer power supplies to smaller, lighter and more efficient switching power supplies. They can be found today in almost all electrical devices that are connected to the 230V mains. While they avoid many disadvantages of their predecessors, they also bring new challenges: First, the system perturbations are not negligible by harmonic and must be limited by standards (EN 61000-3-2, EN61000-3-12). Secondly, the high switching frequencies of up to several hundred kilohertz, on both, the network side and on the consumer side, lead to problems with electromagnetic compatibility. Task of power measurement technology is to help manufacturers optimize their products.