Chapter 3
Hardware Overview
3-6
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Figure 3-4.
Example of Connecting an Isolated Input to a Sinking Output Device
High-Speed Timing
Built from high-speed counters, the high-speed timing circuitry on the
IMAQ 1426 can generate precise real-time control signals for your camera.
Map the output of this circuitry to a trigger line to provide accurate pulses
and pulse trains. Map these control signals to the camera control lines to
control exposure time and frame rate.
Note
For your convenience, the external control for cameras that support the IMAQ 1426
has been preprogrammed into the camera file. You can use MAX to specify the frequency
and duration of these signals in easy-to-use units.
The IMAQ 1426 also allows you to route the external trigger inputs 0-3
onto the camera control lines 1-4. Use MAX to select the source for the
camera control lines. You have the option to choose either the default
control signal that is specified in the camera file or the external trigger input
as the source for the camera control lines.
Acquisition and Region of Interest (ROI)
The acquisition and ROI circuitry monitors incoming video signals and
routes the active pixels to the multiple-tap data formatter and SDRAM.
The IMAQ 1426 can perform ROI acquisitions on all video lines and
frames. In an ROI acquisition, select an area within the acquisition window
to transfer across the PCI bus to system memory.
Vcc
Sensor
Power
IN
+
Current
Limiter
IMAQ 1426
IN
–
NPN (Sinking)
Output Device
Sensor
Common