INFO: OnsetAckDelay Logging in E-Prime [42766]

This article applies to:

E-Prime 3.0

Detail

E-Prime versions 3.0.3.219 and later log a new Attribute, OnsetAckDelay, which flags whether there may be inaccuracies with values logged for OnsetTime due to the issue reported in TIMING: Running on a Windows 11 laptop may negatively impact timing [42409].

What is OnsetAckDelay?

OnsetAckDelay reports the time in milliseconds between the vertical blank and time reported by Windows when the display flip is complete. OnsetAckDelay is a millisecond value recorded in the E-Prime data files when an E-Object has OnsetDelay logged.

NOTE: OnsetAckDelay is not recorded in the data files whenever OnsetDelay is not logged.

What does it mean if my data file records a non-zero value for OnsetAckDelay?

If OnsetAckDelay is greater than 0, this mean that the OnsetTime reported may be inaccurate and may impact the next target OnsetTime. As a result:

• When running with Event timing, display objects may remain on screen longer than the specified Duration (The default setting for RefreshAlignment may help mitigate this issue).
• The "task" component of a TaskEvent defined for the OnsetTime "event" may be delayed.
• The RT and RTTime may be inaccurate because the Object's Input Mask is not armed during the delay period before the OnsetTime is set.

What can I do to mitigate this?

Non-zero values for OnsetAckDelay should only occur when running on Windows 11 laptop. If you are experiencing OnsetAckDelay in E-Prime 3.0 (versions 3.0.3.219 and later), apply the workarounds referenced in TIMING: Running on a Windows 11 laptop may negatively impact timing [42409].

See Also:

RELEASE INFO: E-Prime 3.0 Change History [27275]