1. Evaluating Power Line Environments Using the Echelon PLCA-22 Communication Analyzer using table A.pdf Figure 5-6 and data logging A.pdf

2. When to Characterize the Environment
Some environments have been well characterized using Echelon’s power line technology
Utility applications in Europe
Echelon Networked Energy Services uses repeating to cover all meters
In-Home applications worldwide
Echelon technology provides plug and play in-home communication
Other environments should be characterized
Commercial buildings
Transportation systems
Street or traffic lighting
Irrigation systems

3. Know Which Band to Use Utility Applications Other Applications C-Band
A-Band
C-Band
A-Band
C-Band
Primary
86kHz
Secondary
75kHz
Secondary
115kHz
Primary
132kHz
20k
40k
60k
80k
100k
120k
140k
160k
f(Hz)
20k
40k
60k
80k
100k
120k
140k
160k
f(Hz)

4. Power Line Characteristics
Power line characterization includes measuring:
Attenuation
Noise
Signal distortion 2

5. Power Line Attenuation
Panel
Receiving Node
Transmitting Node
50dB Attenuation
7Vpp
22mVpp
Attenuation(dB) = 20*LOG10(Vtransmit/Vreceive)
Voltage dividers
Wiring inductance
Shunt loads
Panel loading
EMC capacitors
Phase coupling loss

6. Noise Sources Dimmers Switching power supplies Power line intercoms
Triac controlled lights
Produce large impulses at 100Hz or 120Hz
Switching power supplies
Fundamentals at 20kHz to >1MHz
Rich in harmonics
Power line intercoms
3Vpp to 7Vpp from 150kHz to 400kHz
Universal series wound motors
Vacuum cleaners, kitchen appliances, drills
High repetition rate impulses

7. Signal-to-Noise Ratio
Panel
Packets
Received signal levels
Switching
supply noise
Low SNR (6dB)
Amplitude
High SNR
Receiving Node
Frequency
Background noise
SNR (dB)= Signal (dB) – Noise (dB)
Communication performance is largely determined by the SNR of the channels
PL 31xx Smart Transceiver requires ~9 dB SNR for low PER

8. Communication Margin Example
Primary Frequency
24dB
-78dB 3%
<-78dB
>6dB
S/N
0dB
-54dB
>24dB
0.0%
Secondary Frequency
18dB
-72dB
0.5% RX
level
Unack
PER% TX
Attn TX
Attn
Unack
PER% RX
level
0dB
0.0%
-48dB
12dB
S/N
-60dB
Noise
6dB
-54dB
S/N
10%
-60dB
12dB
<-54dB
<6dB
90%
Noise
This example shows 24dB of margin

9. PLCA-22 Communication Analyzers
Supports both A-band and C-band operation
Primary and Secondary frequency level meters
Measure noise when not communicating
Measure signal level when communicating
Measures packet error rate (PER)
With protocol retries turned ‘on’ (Ack4try mode)
With protocol retries turned ‘off’ (UnackPri or UnackSec modes)
Characterize communication margin
Allows attenuating TX signal in 6dB steps while monitoring PER
Measures relative power line phase (0°, +120°, -120°)

10. PLCA-22 Analyzer Front Panel

11. Attenuation and Noise Measurements Demo
Distortion
Switching
Supply
70 dB
50 dB
30 dB
Send
Recv
Setup for measuring attenuation, noise, PER and communication margin
Switching supply “tuned” to primary carrier frequency
Time varying distortion

12. Example Attenuation measurement
Recv
Send
Noise is measured on LED bar graphs with no packets transmitted
Attenuation is measured on LED bar graphs with packets transmitted
When transmitting at 7Vpp attenuation is LED reading plus 6dB
Noise and attenuation can be different for each carrier

13. Measurement Test Sheet
Copy table from PLCA-22 User’s Guide to record test results
Fill in all tan colored squares for each location pair
Fill in blue colored squares if error rate is >3% in tan “%Err” fields

14. Example with Noise Jamming Primary
This direction has 24dB of margin

15. Measure Both Directions
Attenuation, noise & margin often differ in opposite directions
This direction also has 24dB of margin

16. Example with Distortion
Recv
Send
Characteristics of high distortion
High SNR
Primary carrier has low to moderate error rate
Secondary carrier has no errors
Echelon technology distortion correction
Primary has some distortion correction capabilities
Secondary carrier has even more extensive correction capabilities

17. Power Line Attenuation in Homes
World wide in-home attenuation results
169 houses, apartments and condos in 5 countries
1,889 randomly selected socket pairs
99.9% are £78dB
Attenuation
Cumulative probability
96% are £54dB
Attenuation

18. Worldwide In-Home Noise & Attenuation
Low attenuation
Easy communication
Common
Requirements for plug and play communication
Work with 80dB attenuation and low noise
Work to ~50dB attenuation and high noise
Number of
socket pairs
Moderate attenuation
High noise potential
High attenuation
Low noise
Rare
Attenuation dB
Noise (dB 7Vpp)
higher
higher

19. Power Line Evaluation
The PLCA-22 provides evaluation of Echelon power line technology in target environments
Can be used to evaluate key parameters:
Noise level
Signal level
Error rate
Margin
Phase