Studio Technologies 92 - Manual (Page 9)

Model 92 User Guide Issue 1, December 2006
Studio Technologies, Inc. Page 9
No matter whether the Model 92 is manually
or automatically powered up, the voltage of
the internal rechargeable battery is automati-
cally measured. A value of less than 10 volts
will result in a low battery message being
displayed. This is followed by the Model 92
automatically powering down. With a low bat-
tery condition, normal operation can’t take
place unless an external source of nominal
12 volts DC is applied. This power source will
allow Model 92 operation as well as charging
the internal battery. Maintaining the external
12 volt source for up to 24 hours may be
required to fully recharge the battery.
There are four ways that the Model 92 can
be “powered down.” One is manual and
three are automatic. The power on/off button
can be used to manually halt the unit’s oper-
ation; simply tap the power button. Pressing
and holding the on/off button while the unit
is operating will cause a change in the unit’s
operating mode rather than turning off the
unit.
The three automatic power down methods
are inactivity, master/slave command, and
low battery voltage. To maximize the Model
92’s battery operating time, automatic shut-
down will occur after ten minutes of inactivity.
Technically, inactivity is defined as a continu-
ous 10-minute period in which none of the
buttons are pressed. The only exception to
the inactivity timer is if the unit is operating
in the slave mode and data is present on
the master/slave data link. In this case, for
the Model 92 to automatically power down
requires that a power down command be
received by way of the master/slave data link.
The final way that the Model 92 will power
down is if a low battery voltage condition is
detected. Under software control, the battery
voltage is continually monitored. A measure-
ment of lower than 10 volts will result in an
automatic power down.
For operator convenience, upon power down
three operating conditions are saved in non-
volatile memory: operating mode, connector
mode, and channel/pin mode.
Powering the Model 92
Internal Battery
The Model 92’s enclosure includes an inter-
nal 12 volt, 1.3 amp-hour, sealed lead-acid
rechargeable battery. This type of battery was
selected for two reasons: its ability to supply
peak current and long cumulative operat-
ing time. The LED-based displays used in
the Model 92 offer several nice operating
characteristics as well as one limitation. The
first positive is that they are very rugged and
should be able to meet the often-harsh condi-
tions of field broadcast settings. A second is
that they provide a clear indication in low-light
conditions. However, as with most things one
must take the good with bad. The downside
of LED displays is that they require high peak
currents for effective operation. Standard
one-use (disposable) batteries, such as the
ubiquitous 1.5 volt AA style, would simply not
be suitable. The Model 92’s internal lead-acid
battery doesn’t have a problem supplying the
required peak current.
The energy capacity of the Model 92’s inter-
nal battery is such that cumulative operating
time in excess of eight hours can be expected
before recharging is required. In actual ap-
plications it can be expected that it will be
weeks, or even months, between required
charges.
External Power Source
An external source of nominal 12 volts DC
is required for Model 92 operation and battery
charging. The exact voltage value isn’t criti-
cal; anything in the range of 10 to 15 volts is
acceptable. Proper battery charging will