Interlock Symbol; Interlock Example: Source Selection Feedback - Crestron SIMPL Windows User Manual

Crestron SIMPL Windows
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Interlock Symbol

The Interlock symbol will latch an output high on the rising-edge of its
corresponding input. In addition, any other output signal that was previously high
will be latched off, thus this symbol will have at most one output high at any given
time (the exception here is the 'set all' input, discussed below). This property is
called break before make. In essence, this symbol will remember which input was
last driven high, making it very handy when the user has to select from a number of
choices.
The Interlock also has 2 special input terminals, 'clear' and 'set all.' 'Clear' will
cause any output that was previously high to go low. 'Set all' will cause all the
outputs to go high at the same time, the only time that more than one output can be
high simultaneously. This is useful in some specific applications involving non-
volatile memory.

Interlock Example: Source Selection Feedback

Many audio video systems consist of some sort of source selection. That is, the user
can select between a number of sources for viewing and/or listening. A typical
example in a conference room application might be VCR, laser disc, slide projector,
or computer, which may be selected by sending commands to a switcher or a video
projector. Shown below is an Interlock symbol that is implemented to provide
feedback to the user by showing which source is currently selected.
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