Camera interfaces
99
Prosilica GX Technical Manual V2.3.1
Notes on triggering
Trigger rules
•
The end of exposure will always trigger the next readout.
•
The end of exposure must always end after the current readout.
•
The start of exposure must always correspond with the interline time if read-
out is true.
•
Exposure start delay equals the readout time minus the registered exposure
time.
Triggering during the Idle State
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. In this case,
Trigger Latency
and
Trigger Jitter
are as indicated
in the camera specifications.
Term
Definition
User trigger
Trigger signal applied by the user (hardware trigger, software trigger)
Logic trigger
Trigger signal seen by the camera internal logic (not visible to the user)
Propagation delay (
t
pd
)
Propagation delay between the user trigger and the logic trigger
Exposure
High when the camera image sensor is integrating light
Readout
High when the camera image sensor is reading out data
Trigger latency
Time delay between the user trigger and the start of exposure
Trigger jitter
Error in the trigger latency time
Trigger ready
Indicates to the user that the camera will accept the next trigger
Registered exposure time
Exposure time value currently stored in the camera memory
Exposure start delay
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
Interline time
Time between sensor row readout cycles
Imaging
High when the camera image sensor is either exposing and/or reading out
data
Idle
High if the camera image sensor is not exposing and/or reading out data
Table 49: Explanation of signals in timing diagram
User trigger pulse
The user trigger pulse width should be at least three times the width of the trigger
latency.
