User manual

Utility-band BPSK 6.0 kbps PLM PICtail™ Plus Daughter Board User’s Guide

C.1.1.6 DAUGHTER BOARDS PLUGGED INTO A POWER STRIP WITH EMI

FILTERING / SURGE PROTECT FEATURE

Some power strips have Electromagnetic Interference (EMI) filtering or surge protec-

tion devices. These devices filter out the power line noises at frequencies much higher

than the power line frequency (which is 50 Hz or 60 Hz). Since the daughter board uses

a carrier frequency (72 kHz) much higher than the power line frequency, these devices

may attenuate the signal and result in unreliable or sometimes non-functional commu-

nication link between daughter boards. Also, daughter boards will not be able to

communicate if they are connected through isolation power transformers.

C.1.1.7 DAUGHTER BOARDS PLUGGED INTO OUTLETS CLOSE TO NOISE

SOURCES

Power lines can pick up and conduct noise from various noise sources like lamp dim-

mers, electric motors and switching power supplies. Power line noise from these noise

sources can cause degradation in the performance of the power line communication

link. If you notice reduced performance in communication between daughter boards,

try moving them to outlets further away from these noise sources.

C.1.1.8 INTERFERENCE FROM OTHER POWER LINE COMMUNICATION

DEVICES

Other Power Line Communication devices on the power line can cause interference

and performance degradation if they are operating in the same frequency band as this

daughter board. If the interfering device needs to be used simultaneously on the same

power line with the daughter board, please change the operating frequency band of the

interfering device and move it to a power outlet further away from the daughter board.

C.1.2 What is the maximum operational range of these daughter

boards?

Since wall power outlets are connected using wires embedded into the walls, length of

wiring between power outlets is generally greater than the physical distance between

them. It is hard to quote the maximum operational range of the daughter boards since

it depends on many other factors like:

• Structure / architecture of the wiring:

Branches and rings can cause signal reflections and multi-path signals, which can

interfere constructively or destructively with the original signal.

• Age of the wiring:

As wiring deteriorates over time, loose connections can attenuate or reflect

signals.

• Appliances connected on the wiring:

Number, type and distance of appliances from the daughter boards are also

important factors since the appliances can attenuate the signals from the

daughter board and create noise on the power line.

• Quality of components used in the wiring (like copper wires, connectors, switches,

etc).

Despite the Automatic Gain Control (AGC) feature incorporated in the modem

software, changes in the above mentioned factors may change the maximum

possible operational range of the daughter boards.