xiMU - Technical Manual Version 2.10
56
4.3.2.3.
Triggered mode
This mode gives lower FPS compared to
Free-Run
mode. Sensor support two modes of exposure which have impact on camera
signaling.
Sensor timing in global reset release mode
figure 4-2, acquisition mode
–
triggered global reset release
In this mode the timing depends on sum of:
•
Input transition time (t
itr
), depends on:
o
Digital Input Delay - time for changing internal circuit to active state. It is constant for each camera model. For this
camera it is negligible.
o
Trigger delay (t
delay
)
–
delay set in camera to postpone trigger to sensor.
•
Exposure time (t
exps
)
–
Exposure time.
•
Data Readout time (t
rd
)
–
Depends on mode of operation, no direct calculation possible.
•
Post image timeout (t
pos
)
–
time after image readout need by sensor to be ready for next exposure.
Typical times for selected camera models
Camera Model DownS
t
itr
[µs]
t
exp
[µs]
t
eio
[µs]
t
expo
[µs]
t
rd
[µs]
Notes
MU9Px-MH
any
2
0.5
1.5
--
MU181CR-ON
table 4-3, trigger mode w/o overlap, timing
Description:
DownS = Current camera DownSampling (XI_PRM_DOWNSAMPLING)
t
eio
= Trigger (Digital Input) to Strobe (Digital Output)
t
exp
= Strobe (Sensor) to Digital Output
t
delay
= Trigger delay
t
expo
= Start of exposition to Exposure Active Digital Output
LC
= Current Line Count (XI_PRM_ HEIGHT)
t
exps
= Current Exposure Time set (XI_PRM_EXPOSURE)
Minimum trigger period (T
trig_min
)
Minimum trigger period can be calculated using the following formula:
t
trig_min
= t
exps
+ t
rd
+ t
pos
Example for MU9P full resolution
, Exposure time = 500µs, image = 500 pixels width x 200 pixels height
(Full line length is
readout each time including optical black pixels = 2624pixel. Additional lines are readout as well):
t
trig_min
= 500µs +
110
µs
* 21 200
µs =
23.91ms
exposure
rea
do
ut
POS
trigger_delay = 1000 us
FRAME_ACTIVE
EXPOSURE_ACTIVE
TRIGGER
EXPOSURE_PULSE
FRAME_TRIGGER_WAIT
BUSY
t
expo
+t
delay
t
EXP
t
RD
