Specifications

PL 3120/PL 3150/PL 3170 Power Line Smart Transceiver Data Book 201
Transmit Performance Verification
Use the following procedure to verify that the transmit output impedance of the UUT is low enough to adequately drive
low impedance loads.
1. With a single PLCA-22 analyzer in idle mode (no packets being transmitted) and set for the same band of operation
as the UUT, Internal and Line-to-Neutral coupling, connect the analyzer, the UUT, the “5Ω load”, and the Isolator as
shown in Figure 7.8 (if the UUT uses Line-to-Earth coupling to a single power phase then the “7Ω load” should be
used instead).
2. Verify that the UUT application program is not sending messages. (depending on the application it may be necessary
to set the device status to “applicationless” to accomplish this).
3. Press the service switch on the UUT.
4. Observe the primary signal strength LEDs on the PLCA-22 analyzer and check which of the primary LEDs illu-
minate. All primary LEDs up to, and including, the 0dB LED should flash for at least 6 out of 10 service pin mes-
sages from the UUT.
5. Record the result of Step 4 in Table 7.1 at the end of this chapter.
Figure 7.8 Transmit Performance Verification
If the correct LEDs do not illuminate, there might be a problem in the transmit path of the power mains coupling circuit
of the UUT. Possible causes of a reduced transmit signal level include:
• Additional series impedance that has been inadvertently added between the transmit amplifier of the PL Smart
Transceiver and the mains connection.
• The DC resistance of the series resonant inductor in the coupling circuit (L102 in Chapter 4 coupling circuit
figures) is too high.
• The UUT contains a low-current line fuse that has high series resistance.
• A component of the wrong value has been inadvertently used in the UUT.
• Inadequate analog power supply (V
A
) voltage under conditions of full transmit current loading.
Refer to the node checklist in Appendix B for more information about verifying the design of the UUT.
Unit Under Test
(UUT)
service pin
PLCA-22
To power
mains
packet detect LED
ISOLATOR
2.4ž L-N Load
Isolated
Power
Line
5Ω Load (7Ω
load for sgl Ø L-E
UUT)