User`s manual

Operation and Features
3-6 BASLER A302f
DRAFT
Assuming that these general guidelines are followed, the reaction of the camera to a rising
external trigger signal will be one of two cases. In case one, the rising edge of ExTrig occurs when
the camera is not
transferring a captured frame from the sensor to the image buffer. In case two,
the rising edge of ExTrig occurs when the camera is
transferring a captured frame from the sensor
to the image buffer.
Case 1 - Exposure Start When the Camera is not Transferring a Frame
After each exposure is complete, there is a time period of 31.0 ms. during which the captured
frame is transferred from the CCD sensor to the camera’s image buffer.
If the ExTrig signal rises after this time period has ended as shown in Figure 3-3:
• The actual start of exposure will occur between 3 and 4 µs after the rise of ExTrig. For a
given camera, the delay in the start of exposure will be consistent from frame to frame. (The
size of the delay will vary slightly from camera to camera, but will always be in the 3 to 4 µs
range.)
• The IntEn signal will rise between 2 and 3 µs after the start of exposure. For a given camera,
the delay in the rise of IntEn will be consistent from frame to frame. (The size of the delay will
vary slightly from camera to camera, but will always be in the 2 to 3 µs range.)
• The actual length of exposure will be equal to the programmed exposure time plus 4 µs.
To know when frame transfer to the buffer is taking place, the user must monitor the integrate
enabled signal. The frame transfer time period begins on the falling edge of the integrate enabled
signal and lasts for 31.0 ms.
Figure 3-3: Exposure Start After Frame Transfer
*
The camera can be programmed to react to a rising edge of the ExTrig signal or to a
falling edge of the ExTrig signal. We strongly recommend that you program the cam-
era to react to the rising edge of the signal (i.e., active high).
If falling edge triggering is used, the time between the falling edge of the ExTrig signal
and the actual start of exposure is excessively long (at least 90 µs). This occurs due
to the characteristics of the opto-coupler on the camera’s ExTrig input.
TrigRdy
ExTrig
Exposure
IntEn
Frame
Transfer
31.0 ms
Frame N Transfer to the Image Buffer
Exposure
Frame N
Exposure
Frame N + 1
Exposure
Frame N + 2
31.0 ms
Frame N +1 Transfer to the Image Buffer
TIMING CHARTS ARE NOT DRAWN TO SCALE
3 µs
4 µs
2 µs
3 µs
3 µs
4 µs
2 µs
3 µs