Cognex CDC Series Camera Description
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Cognex MVS-8100D and CDC Cameras Hardware Manual
CogLink hardware uses a 40 MHz clock. The encoded 12 bits of serial data sent at a
clock rate of 40 MHz results in a serial bit stream of 480 Megabit/second sent over a
single twisted pair.
Serialized Data Stream
The CDC camera series includes Bus LVDS serializers that break the image sensor data
into packets and convert it into a 10-bit serial data stream for transmission across the
CogLink bus. The MVS-8100D frame grabber has de-serializers that re-convert the
serial data stream and combine the packets into image data.
For communicating camera control information to the camera, the MVS-8100D has
serializers of its own. The CDC camera de-serializes the incoming serial stream and
converts it to camera commands. Packets of command information can be mixed in with
packets of image data in both directions of communication. The CDC camera and the
MVS-8100D both recognize the difference in structure between command packets and
image data packets, and keep the two packet types separate. Thus, CogLink allows
image data and camera control data to flow on the same channel between frame
grabber and camera at the same time.
Addressable Camera Channels
A CogLink channel connection point is characterized as having a pair of Bus LVDS
circuits, a serializer circuit for transmitting data and a de-serializer circuit for receiving
data. A CogLink channel consists of two sets of serializer/de-serializer circuits
connected by a cable.
Each CDC series camera represents one CogLink channel connection point. Various
models of MVS-8100D frame grabbers have one, two, or three CogLink channel
connection points. CogLink channels are counted from zero, so that a three-channel
MVS-8100D has CogLink channels 0, 1, and 2.
Because each CogLink channel is a two-way communication channel, the frame
grabber can query each channel to determine the characteristics and capabilities of the
CogLink device on the other end. Thus, the MVS-8100D frame grabber “knows” which
CDC series camera is connected to each of its channels.
Camera Usage Notes
This section discusses conditions that can produce unexpected results and discusses
ways to work around the conditions.
