Allied Vision Technologies GX1660C, Руководство пользователя, Страница: 29 / 41

GX1660 User Manual
70-0057A-A
Allied Vision Technologies (Canada) Inc.
27
Notes on Triggering
Definitions
o
User Trigger is the trigger signal applied by the user.
o
Logic Trigger is the trigger signal seen by the camera internal logic.
o
Tpd is the propagation delay between the User Trigger and the Logic Trigger.
o
Exposure is high when the camera image sensor is integrating light.
o
Readout is high when the camera image sensor is reading out data.
o
Trigger Latency is the time delay between the User Trigger and the start of Exposure.
o
Trigger Jitter is the error in the Trigger Latency time.
o
Trigger Ready indicates to the user that the camera will accept the next trigger.
o
Registered Exposure Time is the Exposure Time value currently stored in the camera
memory.
o
Expose Start Delay is the delay time from the start of Exposure to valid Trigger Ready. It is
the Registered Exposure Time subtracted from the Readout time and indicates when the next
Exposure cycle can begin such that the Exposure will end after the current Readout.
o
Interline Time is the time between sensor row readout cycles.
o
Imaging is high when the camera image sensor is either exposing and/or reading out data.
o
Idle is high if the camera image sensor is not exposing and/or reading out data.
Rules
o
The User Trigger pulse width should be at least three times the width of the Trigger Latency
as indicated in the Specifications section of this document.
o
The end of Exposure will always trigger the next Readout.
o
The end of Exposure must always end after the current Readout.
o
The start of Exposure must always correspond with the Interline Time if Readout is true.
o
Expose Start Delay equals the Readout time minus the Registered Exposure Time.
Triggering during the Idle State
o
For applications requiring the shortest possible Trigger Latency and the smallest possible
Trigger Jitter the User Trigger signal should be applied when Imaging is false and Idle is
true.
o
In this case, Trigger Latency and Trigger Jitter are as indicated in the Specifications section.