Installation guide

Notice that the Enable checkbox control is also linkable. We know this because of the link icon that appears
next to the checkbox label. This checkbox is a Toggle control. It can have two states: Enabled (checkbox is
selected) and Disabled (checkbox is deselected). You could also have a preset that enables or disables a spe-
cific DR control.
Can I include a switch (connected to a HAL Logic In port) in a control link? If yes, are there
any differences in behavior when using a switch versus a DR in a control link?
Yes, you can connect switches to your HAL's Logic In ports and then include these controls in a control link.
And yes, there are some differences in behavior when including a Logic In control in a control link. Halogen
can read the state of a switch connected to a Logic In port but cannot change the switch's state.
Halogen, however, allows you to configure a Logic In toggle in one of two ways: Momentary or Latching.
Momentary is intended for use with momentary physical switches (surprisingly enough) and when configured
this way, the Logic In port looks for the switch to change from open (not pressed) to closed (pressed) - which
is the same as the transition from logic high to logic low. Each time the Logic In port senses this transition, it
changes the state of the toggle control associated with the port, as seen in the Control palette in the Proc-
essing Workspace. When configured as Momentary, the toggle control is not considered to be a read-only
control because the toggle state doesn't correspond to the state of the Logic In port (logic high or logic low).
Included a Logic In toggle configured as momentary does not place any special restrictions on the link as it
does when you configure the port as latching, as we shall see below.
TIP: Since a Logic In toggle configured as momentary is not considered to be a read-only control, other
controls that participate in a link with the Logic In toggle are able to change the state of the toggle.
This means that you can use DRs or external control system toggles to control a Logic In toggle, which
is handy in some situations, such as controlling the wall toggles in a Room Combine application. For
example, if you have a physical panel with momentary switches and want to use it and also an external
control system to control the wall toggle in a Room Combine block.
When you configure a Logic In toggle as Latching, the associated toggle control in the Control palette of the
Processing Workspace follows the state of the connected switch. When the switch is open, the toggle is
unchecked while when the switch is closed, the toggle is checked. In this configuration, Halogen considers
CHAPTER 3: Key Audio Design Features
112