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Chapter 4
Connecting Lighting and External Devices
The smart camera automatically synchronizes the lighting strobe with the image sensor
exposure. The smart camera always turns the light on before an exposure starts and turns the
light off once the exposure completes. The duration of the light strobe is dictated by the exposure
time. Refer to Chapter 6,
Image Acquisition
, for more information.
When operating in strobed mode, it is important that the strobe duty cycle and strobe duration
are within the specified limits of both the light and the Direct Drive lighting controller. The
strobe duration is the amount of time that the light remains on. The strobe duration limit is the
maximum amount of time that the light can remain on when being driven at the maximum
current. The duty cycle is the ratio of the strobe duration to the frame period, expressed as a
percentage. Refer to the
Maximum Frame Rate
section of Chapter 6,
Image Acquisition
, for
more information about the frame period.
By default, you can set the exposure time to any setting within the range supported by your smart
camera. However, if the smart camera is configured to use the Direct Drive lighting controller
in strobed mode, care must be taken to ensure that the resulting strobe duty cycle and strobe
duration do not violate the limits of the Direct Drive lighting controller or the limits of the light.
For your convenience, the software calculates the resulting strobe duration and duty cycle for
your configured frame rate and exposure time. It then compares them to the limits of the Direct
Drive lighting controller and the limits specified in the associated lighting file. Refer to the
Lighting Files
section of this chapter or the
Maximum Frame Rate
section of Chapter 6,
Image
Acquisition
, for more information.
If the requested exposure time violates the limits of the Direct Drive lighting controller or the
limits for your light as specified in the associated lighting file, the smart camera can use the
requested exposure time, but requires the configured current to be at or below the maximum
continuous
current.
Caution
On devices with a 5 V strobe output or a 24 V strobe output, the software
does not impose any limits on the duration or the duty cycle of the strobe output. You
must ensure that your requested exposure time and the frame rate result in duration
and duty cycle that do not violate the limits of the external controller and/or light(s).
Refer to the
Maximum Frame Rate
section of Chapter 6,
Image Acquisition
, for more
information.
