Echelon LONWORKS PLT-22, User Manual

Page: 96 / 128

The transformers shown in the circuit are 50/60 Hz, 1:1 isolation transformers. The
load (VA) rating of each transformer should be chosen based on the load
requirements of the devices under test. Care should be taken when wiring the
isolator to avoid inadvertent signal coupling between the input and output wiring by
spacing the input and output wires at least 15cm (6") apart.
Test Equipment
In addition to the power mains isolator described in the previous section, the
following “off-the-shelf” equipment will be needed for testing:
• One pair of PLCA-22 Power Line Communications Analyzers (Model 58022).
PLCA-21 Power Line Communication Analyzers are not able to test the
secondary operating frequency of the PLT-22 transceiver and are not
recommended for this test. The PLCA-21 lacks the features required to perform
these tests accurately and should not be used.
• One PL-20 Line-to-Neutral power line coupler, Echelon model 78200-221.
• Two 50 Ω coax cables approximately 25cm (12") long with male BNC connectors
on both ends (AMP 1-221128-x or equivalent).
• A power strip, equipped with both a circuit breaker and 4 or more outlets, which
does not include either surge protection, neon lights, or noise isolation circuitry.
The following additional equipment will need to be constructed for testing:
• A "5 Ω load" circuit, as shown in figure 7.2, should be built in a suitable enclosure
and provided with an appropriate male AC mains plug. Note that the 1M Ω
resistor’s stand-off voltage should be greater than or equal to the peak line
voltage.
1Mž,
±5%,
1/4W
0.47µF ±10%, 250VAC (X2 type)
L
N
E
open
4.7ž ±5%,1W
Figure 7.2 "5 Ω load" Circuit
7-4 Communication Performance Verification