Specifications

Chapter 7 –Communication Performance Verification
194 PL 3120/PL 3150/PL 3170 Power Line Smart Transceiver Data Boo
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Introduction
This chapter describes a simple “black box” testing methodology for determining whether or not the basic
communication performance of a PL Smart Transceiver-based product has been significantly compromised. This
procedure works equally well for products employing L-N or L-E coupling.
The verification procedure described in this chapter is designed to identify gross errors in the implementation of the
support circuitry surrounding the PL Smart Transceiver. Before starting this verification, compliance with all items of
the checklist in Appendix B must first be confirmed. The Appendix B checklist and the performance test described in
this chapter are designed to be complementary. Achieving a passing result for both is essential in order to ensure a
properly functioning device (a performance test that could verify all important parameters independent of the Appendix
B check list would be many times more complicated than the simple tests described in this chapter). Thus any items of
non-conformance with Appendix B must be corrected even if a device passes this Chapter 7 test.
Reasons for Verifying Communication Performance
While each PL Smart Transceiver is thoroughly tested prior to shipment, circuitry external to the transceiver could
compromise the communication performance of the device in which the transceiver is used. Ways in which
communication performance could be compromised include mis-loaded components, inadequately filtered switching
power supplies, circuitry improperly added between the coupling circuit of the transceiver and the power mains, and
deviations from recommended part specifications. Due to the robust communication capability of the PL Smart
Transceivers, it might not be obvious that communication performance has been compromised when testing in a
nominal environment.
Because compromised performance is generally observable only under “corner-case” conditions, failure to verify
performance prior to deployment could result in many marginal units in the field before a problem is detected. It
is therefore essential that the communication performance of every PL Smart Transceiver design be verified
prior to field deployment. This can be accomplished either by self verification, using the procedures given in this
chapter, or by contacting your Echelon sales representative to make arrangements to send the device to Echelon for
confidential evaluation.
Verification Procedure
A summary of the recommended verification procedure is as follows:
1. Create a controlled power line environment that is isolated from typical power mains noise and loading.
2. Provide known load impedances at the communication frequencies of the PL Smart Transceiver.
3. Use the PLCA-22 Power Line Communications Analyzer (model 58022) as a calibrated reference transmitter and
receiver.
4. Test the performance independent of the product's application by making use of the service pin of the Smart
Transceiver and internal statistics features. If the product under test does not have a service pin switch then it will
need to be added to the product for testing purposes.
5. Test for unintentional noise injection and excessive loading by the product under test. This is to ensure that the
device can behave as a “good citizen” on a power line network.
6. Verify that the product's transmit signal level is within acceptable limits. This is done by deliberately loading the
isolated power mains on which the product under test is operating and comparing the output transmission level under
load against a reference level.
7. Verify that the receive sensitivity of the product is within acceptable limits. This is performed using a pair of PLCA-
22 analyzers. The communication signal level of the transmitting PLCA-22 analyzer is gradually decreased and the
receive performance of the product under test is monitored and compared against reference performance levels.
8. All test results can be documented using Table 7.1 at the end of this chapter.