Acquiring Video with Digital Triggering

The system can be configured to provide a digital trigger-out if it includes a CodaHub with analogue acquisition and digital I/O capability. This section describes how this feature can be configured to trigger certain video camera systems to acquire synchronized video data.

Note: Synchronized/Triggered here refers to Start/Stop synchronization, not shutter triggering or frame synch.

Standard CodaHubs include a D-Sub 25-pin female connector on the rear panel for Digital I/O. There are 8 digital output channels, any one of which can be used as start/stop trigger. This is configured in the Acquisition Profile – see below. When running in the output-trigger mode, sets the selected channel to “High” (+5.0V) at the beginning of an acquisition, and sets it back to “Low” (0.0V) at the end of the acquisition.

The following table lists the digital output lines that can be configured to use for triggering:

Signal (TTL) Pin I/O Function
Channel D9 18 Output User (Trigger)
Channel D10 5 Output User (Trigger)
Channel D11 17 Output User (Trigger)
Channel D12 4 Output User (Trigger)
Channel D13 3 Output User (Trigger)
Channel D14 15 Output User (Trigger)
Channel D15 2 Output User (Trigger)
Channel D15 14 Output User (Trigger)
Ground (0V) 1, 6, 8, 13, 16, 19, 20, 23 0V Ground (Chassis)

 

You can configure to trigger digital lines on a CodaHub using the following procedure:

a) Right-click on the “Acquisition Profiles” node under the protocol tree

 
b) From the dialogue that appears, select either “GS Analog Board” if you have an older ActiveHub with a GS16AIO ADC card, or “National Instruments Analog Board” if you have a CodaHub with a NI-6224 ADC card. Also Select “CX1” device to add the CODA system.
C) You will now see the Acquisition Profile dialog. Select the Analog tab,
d) In the “Digital Control Channels” Panel, select the “Trigger Out” check-box. This will activate the Trigger-Out channel selector drop-down list. Choose the required channel and click on OK to save the configuration.

e) You can now connect to the corresponding RTServer hardware to begin acquiring data. You will need a customized lead to connect the digital Trigger Out signal to the trigger input of your video recording system, and the video system control software will need to be configured to start recording when the trigger signal goes high, and to stop recording when the signal goes low.

f) You will also need to configure or note the name and location of the recorded video data file, which needs to be in a location accessible to the computer.

g) Upon completion, you may wish to copy the video data file to a folder within your file system. Simply follow the steps in “Section 3” of this document to configure playback of the newly acquired video along-side CODA data.

Sidebar