Notifications

These are examples for using the Notifications object in Lua. Notifications are a mechanism in which scripts within the same design can communicate with each other and sync control changes without having to wire the individual control pins. Documentation of the Notifications Class is found here.

Text Controller Setup

Controls

Open an instance of Q-SYS Designer Software and drag in a Text Controller component. Add the following controls (see screenshot):

Subscribe: toggle button
Send: trigger button
SendID: text box
SendString: text box
Incoming: LED
ReceiveID: text box
ReceiveString: text box

Next, copy the Example Code to the Text Controller and duplicate it so you have two identical components and scripts.

Notifications Example Code

Copy

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-- Control Aliases
subscribed     = Controls.Subscribe
send           = Controls.Send
transmitId     = Controls.SendID
transmitString = Controls.SendString
incoming       = Controls.Incoming
receiveId      = Controls.ReceiveID
receiveString  = Controls.ReceiveString

-- Variables
noteid         = ""

-- Functions
-- Send a notification at the specified transmit id
function Send()
  local transmit = transmitString.String
  if #transmit > 0 then
    Notifications.Publish(transmitId.String,transmit)
  end
end

-- This function is called whenever a Notification that matches the id is sent from another script
function Receive(id,data)
  receiveString.String = data
  -- Flash the incoming LED for 1 second
  incoming.Boolean = true
  Timer.CallAfter(
    function()
      incoming.Boolean = false
    end,
    1)
end

-- This function subscribes to notifications for the specified receive id
function Subscribe()
  local id = receiveId.String
  local state = subscribed.Boolean
  if state then -- subscribe when the control is toggled high
    if #id > 0 then
      noteid = Notifications.Subscribe(id,Receive)
    end
  else          -- unsubscribe when toggled low
    if noteid ~= nil then
      Notifications.Unsubscribe(noteid)
      receiveString.String = ""
    end
  end
end

-- EventHandlers
send.EventHandler       = Send
receiveId.EventHandler  = Subscribe
subscribed.EventHandler = Subscribe

-- Initialization
function Initialization()
  if #transmitId.String == 0 then transmitId.String = "Enter ID" end
  Subscribe()
end

Initialization()

Notifications

Controls

Running or Emulating the Design