Line-scan

A trigger is used to start the acquisition when the part is in position. Hardware triggers come from the board’s I/O lines. Software triggers come from the application.

After it is started, the acquisition either:

• Continues indefinitely (for web inspection applications)
• Continues for a programmable number of lines (to acquire the image of objects of a known length)
• Continues until an end trigger is received (to acquire the image of objects of a variable length)

An optional trigger delay is available to postpone the beginning of the acquisition for a programmable number of lines.

The Coaxlink & Grablink frame grabber controls the camera scanning rate based on the signals received from a motion encoder. When the parts move faster, the acquisition line rate of the camera increases. When the parts move slower, the acquisition line rate of the camera decreases.

The Coaxlink & Grablink boards interpret A/B signals from quadrature motion encoders to know in which direction (forward or backward) the part is moving.

Optionally, the Coaxlink & Grablink board can be instructed to acquire lines only when the object is moving forward or only when the object is moving backward.

A feature called Backward Motion Cancellation stops the acquisition when a backward motion is detected. The line acquisition automatically resumes when the motion is again in the forward direction, at the exact place where the acquisition was interrupted.

A Rate Converter allows the camera to acquire lines at any programmable resolution lower or higher than the resolution of the motion encoder. This gives the designer incredible freedom and flexibility during the development of the application.

A Rate Divider allows the camera to acquire lines at a resolution lower than the resolution of the motion encoder. It divides the frequency of the incoming encoder signal by a programmable integer.