Echelon FT 3150 Smart Transceiver - Manual (Page 113)

FT 3120 / FT 3150 Smart Transceiver Data Book 107
EN 61000-4 Electromagnetic Compatibility (EMC) Testing
Figure 4.10 Typical EN61000-4-6 Test Set-up for Shielded Twisted Pair (STP)
Figure 4.10 shows the changes in the EN 61000-4-6 test setup to accommodate shielded twisted pair (STP)
networks. The BCI current clamp injects common mode noise onto the STP cable, and the cable shield should be
connected to earth ground with a parallel resistor and capacitor as shown. The resistor is generally 470k
Ω, 1/4W,
5%. The capacitor is generally 0.1uF, 10%, metal polyester, with a voltage rating of 100V or higher.
As indicated in Table 4.2, FT Smart Transceiver-based devices will generally pass the higher 10Vrms (50.9Vpp)
test level with little or no interference with data communications.
Figure 4.11 shows a worst-case example of the EN 61000-4-6 CM noise immunity of FT Smart Transceivers, and
for comparison it also shows the typical immunity of the FTT-10A transceiver (without the FTT-10A Network
Isolation Choke).
Termination
EQUIPMENT
UNDER
TEST (EUT)
HP8656B
SIGNAL
GENERATOR
75W
POWER
AMP
GROUND PLANE
TEST
CONTROL
COMPUTER
FCC
CDN - M3
50 Ω
AUXILIARY
EQUIPMENT
(AE)
Dressler
Alpha 250 / 75W
-6dB
75W
PAD
EMCO
ATT 6 / 75
FCC
CDN - M3
EUT
POWER
AE
POWER
GPIB
50 Ω
FCC BCI - Fischer Custom Communications
Bulk Current Injection Probe P/N F-120-9A
FCC CDN M3 - Fischer Custom Communications
Coupling De-Coupling Network P/N FCC-801-M3-16A
STP
FCC
BCI