Introduction; Definitions - GarettCom 5843HRT User Manual

Models 5843, 5844, 5843S and 5844S
RS232 or TTL
1.

INTRODUCTION

DYMEC Models 5843HRT, 5843SHRT, 5844HRT and 5844SHRT are data communication Link/Repeaters which
allow the replacement of copper wire with fiber optic cable. Link/Repeaters simply convert electrical signals to light
for transmission, then, when received, convert the light signals to back electrical. This is done for RS-232 or TTL
formats.
Link/Repeaters are passive to software protocol. They are not addressable in communication protocols and do not
provide any control logic capability to support communication protocols. Link/Repeaters are designed with several
features that allow easy installation and flexibility in configuring for various communication systems.
Models 5843HRT and 5844HRT are similar except for the method in which they are powered.
Models 5843SHRT and 5844SHRT have the same features and functionality described for the Models 5843HRT
and 5844HRT respectively with the exception that they have single mode optics for use with single mode fiber cable.
This manual makes reference to the Model 5843HRT and Model 5844HRT when describing features and
functionality of the Link/Repeaters. These descriptions generally apply to the Model 5843SHRT and Model
5844SHRT as well. When different, a specific reference is made identifying the particular model(s) and their
variation.
The User should read this manual to fully understand how to use the many features of the Link/Repeaters in an
effective communication system.
1.1

DEFINITIONS

The following terms are used in this manual:
IED:
An IED is any intelligent electrical device capable of RS-232 and/or TTL data communications, such as; a
computer, RTU, PLC, "smart" meter, relay, etc. The IED must have resident software or firmware that
manages the data communication logic, including protocol (formatting and timing), addressing capability (if
required), control logic software "handshaking", and scheduling.
Point-to-Point Configuration:
Two Link/Repeaters connected directly to each other.
Master/Slave Loop Configuration:
More than two Link/Repeaters connected together where the FOC connects the T optical port of one device
to the R optical port of the next unit in the loop. One IED is designated as the Master and controls all the
communication and the other IED's act as Slaves and respond only when specifically polled by the Master.
Peer-to-Peer Loop Configuration:
More than two Link/Repeaters connected together where the FOC connects the T optical port of one device
to the R optical port of the next unit in the loop. Each IED has the capability of becoming loop Master as
allowed by the controlling software.
Echo:
The return of the Master's transmission back to the Master after traveling around the optical loop.
Optical Bus Configuration:
More than two Link/Repeaters connected together in a manner where the Master's transmission is heard by
all IED's and there is no returning echo of this transmission.
NOTE
1-1