Cycle Timing Machine

CIC Cycle Timing Machine block diagram

The CIC timing machine is responsible for the generation of accurately timed events and signals structuring one camera and illumination controller cycle (CIC Cycle).

At every occurrence of a Cycle Start event, the timing machine generates:

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One single pulse on the Camera Trigger signal.

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One single pulse on the Strobe signal.

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One AllowNextCycle event.

Intra-cycle timing

Three GenApi features of the Device module are used to configure the timing of the output signals within a cycle:

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ExposureTime defines the duration of the Camera Trigger pulse.

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StobeDuration defines the duration of the Strobe pulse.

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StrobeDelay defines the time offset from the leading edge of Camera Trigger up to the leading edge of Strobe.

See also: Single Cycle for more explanations and timing diagrams

Cycle-to-cycle timing

The AllowNextCycle event is used by the Cycle Manager to determine when the next Cycle may start.

The position of the AllowNextCycle event is not directly set by the user. Instead, it is evaluated by the driver according to the following user settings:

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The ExposureReadoutOverlap feature of the Camera Model category defines if the camera supports or not the exposure/readout overlapping. If overlapping is allowed, the AllowNextCycle event is issued earlier and faster cycle rates are obtained.

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The ExposureRecoveryTime feature of the Camera Model category defines the minimum time gap required by the camera between two exposures. This feature is relevant when ExposureReadoutOverlap = TRUE and the duration of the exposure phase becomes larger than the duration of the readout phase.

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The CycleMinimumPeriod of the Cycle Control category defines the minimum cycle period. This value may not be smaller than the time required by the camera to perform the image readout!

Some cameras have a data store in the image data path. This enables capturing bursts of images at a higher cycle-to-cycle rate than the camera-to-frame grabber data link can sustain. In that case, CycleMinimumPeriod declares the smallest cycle-to-cycle time that the image sensor can achieve!

See also: Overlapping Cycles - Single timing for more explanations and timing diagrams.