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Specify condition that must be satisfied before trigger executes


When working with the session-based interface, use the TriggerCondition property to specify the signal condition that executes the trigger, which synchronizes operations on devices in a session. For more information, see Synchronization.


Set the trigger condition to RisingEdge or FallingEdge.


Specify Session Connection Trigger Condition

Create a session and add channels and trigger to the session.

s = daq.createSession('ni');
addAnalogInputChannel(s,'Dev1', 0, 'voltage');
addAnalogInputChannel(s,'Dev2', 0, 'voltage');

Change the trigger condition to FallingEdge.

connection = s.Connections(1)
connection.TriggerCondition = 'FallingEdge'
s = 

Data acquisition session using National Instruments hardware:
   Will run for 1 second (1000 scans) at 1000 scans/second.

   Trigger Connection added. (Details)

   Number of channels: 2
      index Type Device Channel MeasurementType      Range       Name
      ----- ---- ------ ------- --------------- ---------------- ----
      1     ai   Dev1   ai0     Voltage (Diff)  -10 to +10 Volts
      2     ai   Dev2   ai0     Voltage (Diff)  -10 to +10 Volts

Click on (Details) to see the connection details.

Start Trigger is provided by 'Dev1' at 'PFI4' and will be received by 'Dev2' at terminal 'PFI0'.

     TriggerType: 'Digital'
TriggerCondition: FallingEdge
          Source: 'Dev1/PFI4'
     Destination: 'Dev2/PFI0'
            Type: StartTrigger