Specifications

PL 3120/PL 3150/PL 3170 Power Line Smart Transceiver Data Book 203
Receive Performance Verification Procedure
The following procedure is used to verify that the receive sensitivity of the UUT is correct. Determination of receive
sensitivity is made by monitoring the physical layer error rate while increasing the level of signal attenuation between a
reference transmitter and the UUT.
1. Insure 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).
2. Set a first PLCA-22 analyzer (referred to as the Recv PLCA-22 analyzer) to the same band of operation as the UUT.
Set it for Recv and UnackPri modes and configure it for Internal, Line-to-Neutral coupling as shown in Figure
7.9.
3. Set a second PLCA-22 analyzer (referred to as the send PLCA-22 analyzer) for the same band of operation as the
UUT. Set it for Send and UnackPri modes of operation and configure it for External coupling. Connect the
PLCA-22 analyzer using the attenuation circuit (30.1kΩ resistor of Figure 7.5) and the PL-20 Line-to-Neutral
coupler as shown in Figure 7.9. Note that the line cord of the Send PLCA-22 analyzer is connected to the power
mains on the input side of the isolator to prevent communications between the two PLCA-22 analyzers via parasitic
line cord coupling.
4. Set the following parameters on the Send PLCA-22 analyzer:
Number of Packets
1000 (1k)
Packet Length
13 bytes
TxVpp
3.5V
Attn
0 dB
Note that 3.5Vp-p TxVpp is used for the Send PLCA-22 even though PL Smart Transceiver-based UUT’s transmit
using 7Vpp. Setting the Send PLCA-22 analyzer to 3.5Vp-p (6dB lower than the 7Vp-p transmit level of the UUT)
provides the opportunity to test for 6dB more receive sensitivity when the analyzer’s Attn is varied in later steps of
this procedure.
5. Connect the UUT test setup as shown in Figure 7.9. Once NodeUtil is running correctly and the start-up screen
shown above is displayed, press the service switch on the UUT. This will cause NodeUtil to register the service pin
message received from the device. Select the “S” command to obtain the status from the UUT (the entry in the
results screen named “Packets received by node” is the number of uncorrupted packets received by the UUT since
the last time the statistics were cleared). Type “Y” at the prompt to clear the status of the UUT. The S command will
be used in the next few steps to obtain the received packet count from the UUT. Be sure to clear the status of the
UUT after each reading.
6. Press START on the Send PLCA-22 analyzer. The test will begin and the receive packet count on the Recv PLCA-
22 analyzer should increment with a packet error rate very close to 0% (<1%). The -60dB LED on the primary fre-
quency signal strength meter on the Recv PLCA-22 analyzer should illuminate, indicating that the received signal is
approximately -60dB relative to the 3.5Vp-p transmit level (-66dB relative to a 7Vp-p transmit level). This level
serves as a starting point; additional attenuation will be added via the Attn function of the Send PLCA-22 analyzer
in Steps 8 and 9.
7. Once the Send PLCA-22 analyzer has sent 1000 packets and all packet transmission has stopped, obtain the received
packet count from the UUT using the NodeUtil S command. Record that value and the packet error rate of the Recv
PLCA-22's analyzer in columns 4 and 5 primary frequency section of Table 7.1 at the end of this chapter. Calculate
the error value as a percentage by subtracting the number of packets received by the node from 1011 and then
dividing by 10 (divide by 1000 then multiply by 100) and record the result in the right most column of Table 7.1.
Refer to the notes at the end of these steps for details of this calculation. If more than 1011 packets are reported as
having been received, this likely indicates that the UUT was not cleared immediately before the test was started. In
this case clear the UUT statistics and repeat the test.