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measurements below 150kHz, and a 9kHz bandwidth filter is specified above
150kHz.
•
For FCC measurements, an input filter which meets the requirements of
CISPR 16 is suitable. The CENELEC EN 50065-1 specification requires that
the filter inside the measuring receiver have even steeper filter skirts than
the minimum required by CISPR 16.
CENELEC EN 50065-1 specifies a 9kHz filter for measurements above 150kHz. The
allowable transmit level is +116dBµV between 95kHz and 140kHz (+134dBµV in
some applications). The CENELEC EN 50065-1 specification limit is +66dBµV
quasi-peak at 150kHz. To make a proper measurement, the filter inside the
measuring receiver must have filter skirts providing at least 60dB of attenuation
10kHz from its center.
The CENELEC EN 50065-1 sub-committee SC 105A (Mains Communicating
Systems) recognized the need for a filter with steeper skirts than the minimum
specified by CISPR Publication 16. As stated in a final draft of an amendment to EN
50065-1 dated January, 1994, "the measuring instrument defined by the minimum
requirements of CISPR 16 is unsuitable for the measurement of mains signaling
equipment that uses a signaling frequency not far below 150kHz," and the sub-
committee SC 105A agreed that "the proper solution would be to specify the
attenuation characteristic of the measuring receiver more closely, receivers being
known to be available on the market."
1
EN 50065-1 Amendment AC specifies a filter
that still complies with CISPR 16 but which has steeper filter skirts. Many spectrum
analyzers, even very expensive ones, do
not
meet this requirement.
The Rohde&Schwarz EMI Test Receiver ESHS30 has been found to have adequate
filter skirts. Although its specification does not
guarantee
adequate filter skirts, two
samples of the ESHS30 test receiver were found to make the measurement reliably.
In addition, care must be taken in setting up the Rohde&Schwarz EMI Test Receiver
ESHS30. The "automatic" mode for setting input attenuation selects an incorrect
attenuation level that will result in an overload condition, which is not properly
reported by the overload indicator on the Test Receiver. The proper attenuation
must be selected using manual mode. A set-up program to accurately run scans for
CENELEC EN 50065-1 compliance testing on the Rohde&Schwarz EMI Test
Receiver ESHS30 is available from Echelon's L
ON
W
ORKS
Developer's Toolbox at
www.echelon.com/toolbox.
An application note from Hewlett-Packard
5
describes a test method for performing
EN 50065-1 conducted emissions tests using Hewlett-Packard EMI test receivers.
The title of the application note is “Conducted Emissions Measurements on Power
Line Transceiver Products.” This application note describes an “off-the-shelf”
external filter and a methodology that allows the measurements specified in EN
50065-1 to be performed accurately.
If the unit under test is found to exceed the applicable conducted noise limit at
frequencies above 500kHz, it may be the result of unintentional coupling from the
node's various digital circuits. If this occurs, improvements in grounding and printed
circuit layout are generally required. Refer to Chapter 4 for a discussion of how to
avoid coupling circuit stray field pickup.
L
ON
W
ORKS
PLT-22 Transceiver User’s Guide
6-7
Содержание LONWORKS PLT-22
Страница 6: ...iv Echelon...
Страница 14: ...1 8 Introduction...
Страница 67: ...LONWORKS PLT 22 Transceiver s User Guide 5 7 Figure 5 3 Capacitor Input Power Supply Schematic...
Страница 92: ...6 10 Design and Test for Electromagnetic Compatibility...
Страница 110: ...7 18 Communication Performance Verification...
Страница 114: ...8 4 References...
Страница 118: ...A 4 Appendix A...