Studio Technologies 93 - Manual (Page 10)

Issue 1, January 2008 Model 93 User Guide
Page 10 Studio Technologies, Inc.
anything additional, up to 100 milliamperes
more, will be used by the charging circuitry.
As such, a power supply with a minimum of
250 milliamperes is recommended.
A 120 volt AC input, 12 volt DC, 300 mil-
liampere, plug-in-the-wall power supply is
included with each Model 93. While good
quality, it’s a generic unit that can be eas-
ily replaced or substituted (Studio Tech-
nologies part number 10320; Digi-Key part
number MT7146). The connector required
for the power supply source is 2.1 x 5.5 mm
with positive on the inner lead. The DC input
connector on the Model 93 is a locking
type, allowing a locking mating connector
to be attached if desired.
Stand alone, the Model 93 can function
correctly as long as the battery voltage is
10 volts or greater. It will also function cor-
rectly whenever an external power source is
connected. This flexibility is due to the pres-
ence of a secondary power supply, located
on the Model 93’s printed circuit board, that
generates the 5 volts DC required for the
logic circuitry.
The Model 93’s internal battery will charge
whenever an external power source is con-
nected. The unit doesn’t have to be “pow-
ered up” for battery charging to take place.
The time required to fully recharge the bat-
tery will depend on its discharge state
at the time charging begins. Allowing 24
hours will ensure that full recharging will
always take place, although a shorter dura-
tion will probably be sufficient. The Model
93 implements a constant voltage charging
method. This minimizes the chance that bat-
tery overcharging will take place. Keeping
an external power source connected to the
Model 93 for long durations, or even perma-
nently, won’t cause damage to the battery.
Note that a text message will be displayed
whenever the Model 93 is operating under
battery power and an external power source
is then connected. To indicate that the exter-
nal source has been detected, the LED dis-
plays will briefly show the message CHRG.
Removing an external power source will not
result in any message being displayed.
System Modes
The Model 93 can be set to one of four
overall ways of operating. These are called
the system modes and the choices are
local, master-male active, master-female ac-
tive, and slave. Refer to Figure 3 for details
The local system mode is intended for test-
ing W1 cable assemblies where both ends
will be connected to the same Model 93.
This is the default system mode and the one
that will most commonly be used. The other
three system modes are provided so that
two Model 93 units can work together in
a master-slave arrangement. This unique
capability allows testing of cable assemblies
that are permanently installed or already
deployed in a facility or venue. Specifically
this is the situation where the connectors
on both ends of a single W1 cable assem-
bly are not accessible for connection to the
same Model 93.
To select the desired system mode, press
and hold the power button. The four
modes will “cycle” through. Release the
power button when the appropriate indi-
cator light is active. The selected system
mode will generally remain in effect until
it is manually changed. Power cycling the
Model 93 will not cause it to change or re-
vert to a “default” setting. The exception
is in the master-slave situation where a
Model 93 configured for master-male active
or master-female active can “force” its com-
panion unit into the slave mode.