Specifications

Crestron SIMPL Windows Software
However there are some drawbacks to this method. First, programs written in this
matter can be difficult to read, in that you must trace the signal completely to
determine what events it triggers. This is made easier by the ‘Show Routings’
command in SIMPL Windows. The second drawback is more serious: what if you
wanted to provide individual control of the screen, the projector power, and the
lighting presets? With the example shown above, these three functions are tied
together and can never be controlled independently. Even if you think that this type
of control is not needed, it may be needed in the future, requiring you to make
significant changes to your program.
To avoid this limitation, we can add logic to the program. An intuitive solution uses
OR symbols to gather all the events used to trigger a single event. For example, if we
want to lower the screen on the ‘system on’ button press, or when the ‘screen down’
button is pressed, we use an OR to accomplish this. The figure below shows an
equivalent program to the one above, now using OR symbols, thus allowing for
independent control of each function.
Multiple OR symbols for discrete control
Lights_Scene_2_OR
VProj_On_OR
Screen_Down_OR
Lights_Scene_2
Vproj_Power_On
Screen_Down
in1
in2
out
OR
in1
in2
out
OR
press115
press116
press117
press118
press119
press120
press121
press122
press123
press124
press125
fb115
fb116
fb117
fb118
fb119
fb120
fb121
fb122
fb123
fb124
fb125
Touchpanel
in1
in2
out
OR
This example is more flexible, but also has drawbacks. First, like the previous
example, programs will be hard to follow, especially as they get larger; for each
function you must trace back through an OR symbol to determine which events
trigger it. Second, as your program grows there may arise other occasions where you
need to trigger a function. For example, perhaps you want to lower the screen
automatically every time a source is selected. This can be handled by simply
increasing the number of inputs to the appropriate OR symbol, but ultimately this
leads to a ‘messy’ and hard to debug program.
This now leads us back to the Buffer symbol. Remember that the output signals on a
Buffer may be tied to existing signals that are driven by system inputs or by other
Buffers. This enables us to create an elegant program that uses one or more Buffers to
handle all the multi-event triggering. Shown below is a program that performs more
functions than the OR symbol example above, yet uses only a single symbol.
Primer – DOC. 6253 Crestron SIMPL Windows • 45