Manual

Model 45A User Guide Issue 3, August 2015
Studio Technologies, Inc. Page 25
the nulling process take place. But unless
there’s a really good reason, configuration
DIP switch 5 should always remain in its off
(down) position.
Technical Notes
Software Version Display
A special Model 45A power-up sequence
allows the unit’s software version number
to be displayed. This is useful when work-
ing with factory personnel on application
support and troubleshooting situations. The
five “from” 4-wire LEDs are used to display
the major release number with a range of
1 through 5. The five LEDs associated with
“to” 4-wire channel 1 are used to display
the release sub-number which ranges from
1 through 5. Refer to Figure 12 for a de-
tailed view of the LEDs and the correspond-
ing software version numbering scheme.
The Model 45A’s initial software release
is version 1.1 which is represented by the
bottom LED of each column being lit.
To display the Model 45A’s software ver-
sion is very simple. From the powered-
down state, press and hold the auto null
button. While continuing to press the auto
null button, apply power either by connect-
ing an external 24 volt DC power source
or a powered intercom circuit. The normal
power-up sequence will not occur but
instead one LED in the status column will
be lit and one LED in the column associ-
ated with “from” 4-wire channel 1 will also
be lit. As previously described, these two
LEDs represent the unit’s current software
version. After the software version number
has been “read” the auto null button can
be released. At this time the unit will begin
its normal power-up sequence.
Note that while it’s easy to determine which
software version is loaded into the Model
45A a trip back to the factory is required
to update it. The 8-bit microcontroller that
provides the unit’s logic “horsepower”
also includes internal FLASH memory. This
nonvolatile memory is used to store the
Figure 12. Detail of front panel showing the status LEDs that display
the software version. In this example, the software version is 1.3.
Major Release Number Release Sub-Number
O 5 .5 O
O 4 .4 O
O 3 .3 
O 2 .2 O
 1 .1 O