WattMaster WM-WCC3-TGD-01B - Manual (Page 42)

I. INTRODUCTION
WCC III Technical Guide I-20
Fiber Optic Converter
Introduction to Fiber Optics
In recent years it has become apparent that fi ber-optics are steadily
replacing copper wire as an appropriate means of communication
signal transmission. They span the long distances between local
phone systems as well as providing the backbone for many network
systems. WattMaster Controls, Inc. has designed an RS-485 to
Fiber Optic device to work with the WCC III communication
network.
A fi ber-optic system is similar to the copper wire system that fi ber
optics is replacing. The difference is that fi ber optics use light
pulses to transmit information down fi ber lines instead of using
electronic pulses to transmit information down copper lines.
The WattMaster Controls, Inc. Serial to Fiber Optic Converter
for the WCC III system consists of two parts. The FOSTC Serial
to Fiber Optic Converter and the FOSTC Serial to Fiber Optic
adaptor board.
Fiber Optic Adapter Board
The PL102334 FOSTC Fiber Optic Adapter Board provides for a
two-wire, RS-485 interface to the FOSTC Fiber Optic converter
for the WCC III / SAT III communications loop. It is also the power
supply for the FOSTC Serial to Fiber Optic Board.
RS-485 BIAS Jumpers
The RS-485 BIAS jumpers for the terminating resistors need to
be ON only when there is no WCC III - MCD connected to the
FOSTC fi ber optic adapter board’s SAT RS-485 communication
loop.
The RS-485 BIAS jumpers for the terminating resistors need to
be OFF only when there is a WCC III –MCD connected to the
FOSTC fi ber optic adaptor board’s SAT RS-485 communication
loop.
It is recommended that this circuit board has its own 24 VAC
transformer for optimal isolation on the RS-485 side.
The LED D3 “POWER” will light when the PL102334 circuit
bard has power (24VAC) applied to it.
The LED D4 “COMM” will blink with the fl ow of data to and
from the RS-485 communications loop.
Fiber optic cabling has inherent resistance to EMI/RFI and
transient immunity, making it ideal for industrial and utility data
communication applications.
Figure I-16: WattMaster Controls, Inc. Serial to Fiber Optic Converter for the WCC III System