Echelon LONWORKS PLT-22, User Manual

Page: 75 / 128

Table 5.5 lists the endpoints of the straight lines shown in figure 5.7, and table
5.6 lists those shown in figure 5.8.
Table 5.5 Switching Power Supply Input Noise Limits for CENELEC EN 50065-1
Compliance
Frequency(kHz) Noise Level (dBuV):
Quasi-Peak Detector
Noise Level (dBuV):Average Detector
9 89 N/A
110 68 N/A
110+ 30 N/A
140 30 N/A
140+ 66 56
500 56 46
500+ 56 46
5000 56 46
5000+ 60 50
30000 60 50
Table 5.6 Switching Power Supply Input Noise Limits for FCC Compliance
Frequency(kHz) Single Carrier Frequency
Noise Level (dBuV):
Quasi-Peak Detector
Dual Carrier Frequency
Noise Level (dBuV):
Quasi-Peak Detector
9 100 89
40 100 76
40+ 80 76
50 80 75
50+ 80 75
110 80 68
110+ 80 30
125 80 30
125+ 30 30
140 30 30
140+ 70 60
450 70 60
450+ 48 48
30000 48 48
!
A power supply that does not meet the appropriate noise mask for the
power supply input may require a filter between the local switching
power supply and the power mains. A filter example which both attenuates
switching supply noise and provides >200 Ohm input impedance is shown in
figure 5.9. Note that both inductors must be rated for the peak AC current
drawn by the power supply; the 3.3 Ohm resistor should have a power rating
consistent with the AC current drawn by the power supply, and its voltage drop
should be verified as acceptable.
L
ON
W
ORKS
PLT-22 Transceiver's User Guide 5-15