Studio Technologies 41 2013 - Manual (Page 15)

Model 41 User Guide Issue 3, November 2013
Studio Technologies, Inc. Page 15
by one. A delay is built into the channel
selection process allowing a user to
move, for example, from channel 1 to
channel 3. By pressing the button twice
in rapid succession channel 2 will be auto-
matically skipped.
Unique to the Model 41 is its auto scan
feature. Pressing and holding the button
for two seconds will cause this feature to
begin operation. In this mode the monitor
source automatically “steps” through each
IFB output, pausing for eight seconds
before moving on to the next. Ideally, this
will allow technical personnel to observe
a problem through casual viewing of the
Model 41’s front panel.
DC Voltage Monitoring
The Model 41’s microcontroller integrated
circuit, under software control, “watches”
to ensure that the DC voltage present on
pin 2 of each IFB output connector is at an
acceptable level. The low-voltage thresh-
old for the Model 41’s 30 volt DC output
is 24 volts. As discussed in the previous
section, the four LED indicators display
which IFB channel is currently selected for
audio monitoring. In addition, the LEDs
provide an indication of the DC voltage
status on the IFB outputs. An LED will
“flash” at a moderate cadence if the volt-
age on pin 2 of its associated IFB output
falls below the acceptable value. This can
be caused by a temporary over-current or
short-circuit condition, such as when inter-
connecting user devices to Model 41 IFB
outputs using faulty portable cabling.
An under-voltage condition that’s pres-
ent for a continuous 4-second period will
cause a fault condition to be recognized.
The status LED associated with the prob-
lem IFB output channel will indicate this
condition by flashing at a faster rate. In
addition, the output voltage on that spe-
cific IFB output channel will automatically
shut down to an essentially off condition.
A 10-second “cool-down” period will then
take place, after which the output voltage
will again become active. As soon as the
output is enabled normal output voltage
monitoring will again take place. A con-
tinuous short-circuit presented to an
IFB output will result in a continuous
4-seconds-on/10-seconds-off error cycle.
It’s important to note that during the 10-
second off period no voltage monitoring
takes places. Removing the fault condition
will not result in the output voltage imme-
diately turning on again; the 10-second
shut-down period must first elapse.
Operating Parameters
As expected with professional equipment,
whenever AC mains power is discon-
nected from the Model 41, the present
operating state will be stored in nonvolatile
memory. Specifically, the IFB output chan-
nel selected for audio monitoring and the
status of the auto scan function will be
saved. This ensures that upon subsequent
power up the unit will return to its previ-
ous operating state. If, for example, the
auto scan function was active when the
Model 41 was powered down, auto scan
will begin once AC mains power is again
connected.