Not Symbol Example: Automatic Camera Control; Or Symbol; Or Symbol Example: Volume Un-Mute - Crestron SIMPL Windows User Manual

Crestron SIMPL Windows

OR Symbol

Primer – DOC. 6253

NOT Symbol Example: Automatic Camera Control

Sometimes a device provides the opposite signal than you want. For example, say
your control system is set up to receive contact closures from an automatic
microphone mixer, indicating which microphone has just been spoken into. In a
video conferencing application, these closures might be used to point the camera
directly at the speaker. However, suppose that instead of supplying a closure each
time a microphone was spoken into, the relays were normally all closed and that it
supplied an open contact to signify a microphone trigger. You could pass each
incoming signal into a NOT symbol to first invert its level. The output signals could
then be used to trigger camera presets somewhere else in your logic.
OR Symbol
The OR symbol will drive its output signal high whenever any of its inputs are high.
Looking at the figure below, you could say that 'signal_out' is high whenever
'signal_1_in' OR 'signal_2_in' are high.
The truth table for a 2-input OR symbol is shown below.
Signal_In 1 Signal_In 2 Signal_Out
Low Low
Low
High
Low High
High High
Note from the truth table that when both of the input signals are high, the output is
still high. If you need an operation where the output is high when only one of the
inputs are high; you can use an Exclusive OR (XOR) symbol.
Note that the OR symbol has an arbitrary number of inputs (determined by the
specific application), and a single output. That is, a 20-input OR symbol will have a
high output whenever any of the 20 input signals are high.

OR Symbol Example: Volume Un-mute

As an example, consider volume control, which typically consists of up, down, and
mute buttons. When the audio has been muted, you may want to un-mute it
automatically if the volume up or down buttons were pressed. To accomplish this
you could use an OR symbol like the one shown. Note that additional logic is needed
to finish this example, and this will be covered in a later section.
Low
High
High
High
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