- 8 -
TC2100 DM
User's Manual
Ver. 1.6
MNL-21000-01-16
Dual Master Mode Description
Dual Master Mode Setup
To enable TC2100 as “Dual Master”
simply move switches 3, 4, 5, and 6 of
the “internal DIP switches” (as SW1
on PC board) to the right (on) posi-
tion. Switches 4 and 5 are designed
for “Dual Master Mode Prolong timer
setup,” they will determine how long
the unit will take (1, 2, or 4 second) to
change from a master unit to a slave
unit.
TC2100 has a special feature called “Dual Master.” When a unit is enabled as “Dual Master,” it can be either
a slave unit or a master unit. It is a very useful tool against major cable breakage and unit malfunction
(especially if the master unit is the source of the problem), because one of the slave units can be a backup
master unit.
The purpose of having one of the slave units in “Dual Master Mode” is to provide a backup master unit when
necessary. In most cases, TC2100’s standard self-healing ring capability is able to prevent network break
down from cable breakage or unit failure. However, there are limitations, such as: 1.) the master unit is the
source of the problem. 2.) The master unit is isolated from rest of the network. 3.) Both A-ring and B-ring
break in more than one location, which split the network into half. The “Dual Master mode” is designed to
prevent these problems from happening.
Warranty Note:
You must contact the Technical Support Department at TC Communications, Inc. for approval
before opening any device for internal settings. Otherwise, the warranty will be void.
Operation of Dual Master mode
When a unit is in “Dual Master” mode, it can be either a slave unit or a master unit depending on following
conditions:
1.) If TC2100 receives electrical signal from Host Controller, it will become a master unit.
2.) If TC2100 receives electrical signal from local RTU, it will become a slave unit.
3.) If TC2100 doesn’t receive any electrical signal, it will become a slave unit.
As shown in Figure 9, “unit 1” is set as a dedicated master unit; “unit 2” and “unit 4” are set as dedicated
slave units. “Unit 3” is set as “Dual Master Mode” unit. During normal condition “unit 3” will function as
a slave unit, and the network operates like a dual ring topology. If there is cable breakage or malfunction,
“unit 3” can become a master unit to prevent network from break down, such as demonstrated in case one
and two in following pages.