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Validating experiment timing is a key step in launching a new study or reactivating an older one. This can be achieved through running a Timing Test; the results of which will allow the comparison between the time when the stimulus presentation system states that the stimulus is presented, and the time that the AV Device physically detects the presentation of the stimulus as it would be presented to the subject. 

This article will lead you through the necessary steps involved in successfully setting up a Timing Test for Net Station 5, E-Prime and EENS using the AV Device. To overview, the steps include how to: 

1. Set up the AV Device

2. Configure the DIN interface in Net Station 5.4 Acquisition 

3. Start the E-Prime timing test

4. Interpret the timing results using the Event Timing Tester Net Station Utility

1. Setting up the AV Device

     a. Connect the DB9 end of the DB9 to Hypergrip adapter cable to the DINs Output of the AV Tester. 

b. Connect the blue and white Hypergrip end of the DB9 to Hypergrip adapter cable to the first blue DIN port on the back panel of the Net Amps (DINs 1-8).

     c. Connect the power supply cord to the AV Tester's port labeled "9 VDC" located at the top of the AV Tester.

     d. Connect other end of the power cable to an AC power socket. 

     e. If you are testing a visual or movie stimulus, connect the photocell jack into the photocell port on the front of the AV Tester, as in the image below, and continue through to step g. If you are testing auditory stimuli, connect the supplied audio cable to the audio port on the AV Tester and the other end to the headphone jack on the PC, and skip to Part 2. 

     f. Fit the photocell into its receptacle in the assembled photocell holder. 

     g. Position the photocell so the tip is touching the subject's monitor in the location where the stimulus will appear on the screen. 

2. Configuring the DIN interface in Net Station 5.4 Acquisition

     a. Launch Net Station Acquisition

     b. With streaming "Off", configure an existing Workspace or Create a new one. Note that the Default Workspace cannot be modified, but can be cloned, modified and then renamed. 

     c. Configure the Hardware section for the DINs number you need. For visual stimulus testing with the photocell, choose DIN3; for audio stimulus testing with the audio cable, choose DIN2 (refer to Part 1, step e. above). 

 3. Start the E-Prime Timing Test

In this example, we are using the MovieTimingTest.es2 

     a. Open the E-Prime Production Testing folder located on the desktop of the E-Prime computer. 

     b. Open the file and click the Running Man button, or F7. 

     c. Follow the on-screen instructions, which will guide you in the proper placement of the photocell holder.  If you wish you configure your own E-Prime experiment, please refer to the AV Device Manual. 

4. View your Timing Test Results

     a. Quit Net Station

     b. Navigate to the Event Timing tester (Applications>EGI>Utilities) and double click to launch it. 

     c. From the Event Timing Tester menu, choose File>Open and navigate to the Net Station MFF recording located in the Net Station Sessions folder.       

     d. In the Event Timing Tester window, select the desired Stim Event Code (ECI) and DIN event codes. For example, for the Movie Timing Test, you would select stm+ for Stim Event Code and DIN3 for the DIN Event Code. 

     e. Click the Create Timing Table button and review the results. You should not see more than +/1 3 ms variation in the Offset.