Dalsa PC2-Comp Express OC-P2EM-COMP0, User Manual

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PC2-Comp Express Theory of Operation
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External Trigger
An external trigger allows image acquisitions to be synchronized to external events. With this mode
enabled, when the PC2-Comp Express receives a trigger signal, the acquisition begins with the next
valid frame.
PC2-Comp Express provides one TTL external trigger input. It is possible to emulate an external
trigger using a software trigger generated by a function call from an application.
The incoming trigger pulse passes through a debouncing circuit to ensure that no voltage glitch would
be detected as a valid trigger pulse. The time constant can be programmed from 0
μ
s (off) to 255
μ
s.
Any pulse smaller than the programmed value is blocked and therefore not seen by the acquisition
circuitry. A minimum pulse of 100 nsec is recommended for proper operation.
Note: DALSA recommends that a debouncing value always be used (even a minimal 1
μ
s delay) to
avoid the effects of any undefined electrical state when passing from TTL low voltage (0.8V) to TTL
high voltage (2.0V).
TTL external trigger is available on J3 pin 2 (see "J3: DIN 8 Pin, Trigger Input" on page 37). and can
be directly connected to a TTL voltage source. The following table defines the electrical specification.
Electrical
parameters Description Value
V
IL max
Maximum voltage for low 0.8 V
V
IH min
Minimum voltage for high 2 V
Sapera parameters for External Trigger:
CORACQ_PRM_EXT_TRIGGER_ENABLE = CORACQ_VAL_EXT_TRIGGER_ON
CORACQ_PRM_EXT_TRIGGER_DETECTION = {CORACQ_VAL_RISING_EDGE,
CORACQ_VAL_FALLING_EDGE, CORACQ_VAL_ACTIVE_HIGH, CORACQ_VAL_ACTIVE_LOW}
CORACQ_PRM_EXT_TRIGGER_DURATION: Debouncing duration
CORACQ_PRM_EXT_TRIGGER_FRAME_COUNT: Number of frames to acquire per trigger
In CamExpert, these parameters are located under the ‘External Trigger Parameters’ tab.