Studio Technologies 5130 2013 - Manual (Page 11)

Model 5130 User Guide Issue 5, July 2013
Studio Technologies, Inc. Page 11
Model 5130
Party-Line Interface Module
Auto Null and Operating Mode
There is one situation where pressing the
auto null button will not start the auto null
process. If the Model 5130 has been con-
figured for operating mode 1, a minimal
amount of DC current must be drawn from
the party-line interface to indicate that a
2-wire party-line device has been con-
nected. If this threshold (15 milliamperes)
has not been reached the circuitry, under
firmware control, assumes that nothing has
been connected to the XLR connector as-
sociated with the party-line interface and
the auto null process will not start. (Techni-
cally, if nothing has been connected to the
party-line interface, performing an auto null
sequence would result in an inappropriate
2-wire-to-4-wire converter calibration.) If the
auto null button is pressed and the minimum
DC current level has not been reached the
auto null LED will flash six times and then
stop. This indicates that the button press
was recognized but that the minimum DC
current draw requirement was not met.
If the Model 5130 has been configured for
operating mode 2 the auto null function is
always available. A minimum amount of DC
current is not required to be drawn from the
2-wire party-line interface. This operating
mode was provided for applications where
the 2-wire party-line interface is intercon-
nected to a valid device (or devices) but
DC current is not being drawn. An example
of this would be connecting Studio Tech-
nologies’ Model 200-Series announcer’s or
producer’s consoles which are being locally
powered. (Model 200-Series devices can
be powered by the Model 5130 but in most
cases an external source of 24 volts DC will
be connected.) In this case each Model 200-
Series device would be a completely “valid”
connection to the Model 5130 although no
DC current would be drawn by it.
To view and, if desired, change the operat-
ing mode refer to the Technical Notes
section of this guide.
Level Meters
The four audio level meters on the Model
5130 are calibrated differently from typi-
cal “VU” meter scales. Their “steps” are
labeled in reference to the level of the
signals being sent to, and received from,
the party-line interface. The ballistics of
the meters is also different, being a cross
between VU and peak.
During operation the green “0” LEDs will
light in response to audio levels of –10 dBu
being present on the party-line channels.
When a 5130S (SMPTE level) module has
its “0” LEDs lighting they correspond to
+4 dBu being present on its associated
4-wire audio input or output connections.
In the case of a 5130E (EBU level) module
the audio input and output level would be
0 dBu.
The four green LEDs of each meter in-
dicate that the levels are in the normal
range. The yellow LED lights when a signal
is approximately 6 or more dB above the
nominal (–10 dBu to or from the party-line
channel) level. Optimal signals will result in
the four green LEDs lighting almost solidly
with the yellow LED lighting only on peak
signals.
Party-Line Power Supply
One or more party-line user devices can
be directly connected and powered by the
Model 5130’s party-line interface. The only
restriction on the number of user devices
that can be connected is that the total
current draw must be equal to or less than
180 milliamperes. Broadcast-standard