1 Overview

Microchip provides a set of PLC reference designs which passes all required certifications and performance tests to ensure a successful field deployment.

This application note describes how to perform these tasks:
  • Check the performance of a prototype at PHY layer level.
  • Compare the performance of the prototype to Microchip PLC reference designs.
  • Adjust the PHY layer configuration of the PLC modem to improve the performance.

By analyzing and comparing the behavior of the physical layer of the HW prototype with the behavior of Microchip PLC reference designs, customers can increase the confidence in their designs.

This application note is valid for any G3-PLC or PRIME design regardless of the communication frequency band.

Important:

This application note describes some tests to evaluate the G3-PLC or PRIME PHY performance of any prototype based on any Microchip PLC reference design.

For G3-PLC: In any case, these tests cannot replace the Performance Test Suite for G3-PLC Device Certification and G3-PLC Conformance Tests Suite Specification defined by the G3-PLC Alliance nor ensure that they will be passed. They are only the first step to pass them.

For PRIME: In any case, these tests cannot replace the PRIME Certification TestBooks defined by the PRIME Alliance nor ensure that they will be passed. They are only the first step to pass them.

Final PLC products may comply with additional normative or specifications depending on the legal terms of the end purpose. Describing the complete set of specifications to comply by the final product is out of scope of this document.

Attention: Microchip strongly recommends following the PLC design guidelines available together with the following documents:
  • PLC Hardware Design Guidelines
  • Crystal Selection Guidelines

This document describes a method to evaluate the PHY performance of any PLC design where a calibration process was already carried out. The main goal of the device calibration is to adapt the PLC transmission to be compliant in G3-PLC with section 2 of the Performance Test Suite for G3-PLC Device Certification and in PRIME with the Electrical Specification section of the 6. DUT must be EN50065-1 /-2 /-3 /-7 compliant.

The features required by the standards to be complied are the following:

  • Section 6.3.1.2 of EN50065 standard. TX power < 134 dBμV over CISPR 16-1 LISN (impedance around 50Ω).
  • Section 2.1 of G3-PLC device certification. A minimum signal level is not defined when DUT is connected to an LISN with impedance of 2Ω (PRIME LISN). Anyway we defined a TX power > 120 dBμV over PRIME LISN (impedance of 2Ω).

Due to that mismatch between transmission power requirements of section 6.3.1.2 of EN50065 standard and section 2.1 of G3-PLC device certification, our devices have to transmit in two different ways:

  1. Certification Mode (AKA “High Z” mode or “High Impedance” mode).
  2. Field Mode (AKA “Very Low Z” mode, “Very Low Impedance” mode).
Important:
  1. Normal operation is “Field mode” and every device in the field must transmit in this way. This mode is fully compliant with G3-PLC and PRIME Spec.
  2. The Microchip PLC device is able to select the transmission mode automatically depending on the observed amplitude of the transmitted signal (directly related with impedance). This feature lets the same FW to be compliant with both EN50065 and G3-PLC or PRIME device certification.

The process to calibrate the PHY parameters to be used by the automatic transmission mode are detailed in Physical TX Calibration. This is a process necessary depending on the results obtained when evaluating the communication performance detailed in SNR and EVM Tests. Additionally some design problems like noise on the PLC communications band and XTAL configuration can be analyzed using Noise Test and Frequency Deviation sections.

Microchip provides open source software tools to allow the automation of any process that involves serial communication with Microchip PLC devices.