EDT, Inc.
2019 April 29
27
VisionLink F-series
Troubleshooting
Problems With Bandwidth
To prevent timeouts and data loss caused by bandwidth problems, you’ll need to determine the bandwidth required by
your camera and verify that the board and the host system can sustain the required throughput.
Bandwidth requirements depend on the
camera’s
pixel clock speed, the number of bytes per pixel, the number of taps,
and the number of channels. To calculate bandwidth requirements, use this equation...
pixel clock speed * taps * bytes/pixel = total bandwidth
NOTE
The pixel clock speed, not the frame rate, affects bandwidth requirements. If data loss is a problem, increasing the
delay between frames probably will not help.
Cameras that output 10
–
16 bits per pixel will require two bytes per pixel of bandwidth. Therefore, a camera that has a
40 MHz pixel clock, two taps, and 12 bits per pixel requires system bandwidth of...
40 * 2 * 2 = 160 MB per second
You can ease this constraint by running the camera in a less demanding mode
—
for example, you can often run two-
tap cameras in single-tap mode, or 12-bit cameras in 8-bit mode.
Other tips on solving bandwidth problems include...
•
to verify that your setup meets bus and throughput requirements.
•
Consider the number of cameras and the speed of the cameras you are using. The bus bandwidth may be adequate
for some configurations, but inadequate for configurations with more or faster cameras.
•
Consider the number of frame grabbers or other devices connected to the bus; using multiple devices on a single
bus can reduce bandwidth, sometimes considerably.
•
Verify that your bus has the minimum number of required (fully connected and usable) lanes
–
that is, at least four
lanes for the F4 board.
Problems Acquiring Images With EDT Applications
If you have problems with image acquisition when using EDT applications, try the suggestions below.
•
Verify that the camera device is on and is receiving power.
•
Verify that all interface cable connections are working properly: Turn off the camera and power off the system; un-
plug the cable at both ends; reattach the cable at both ends; and turn on the system and camera again.
•
Try a different cable, if available.
•
Try a different camera, if available.
•
Verify that the EDT installation package was installed correctly and that the driver is running and can see the board.
To do so, in the installation directory (see
), go to the command line and enter...
pciload
If you see no information about your EDT board, then a problem occurred during installation.
To resolve it, one at a time, try...
—
cycling system power;
—
moving the board to a different slot;
—
uninstalling and reinstalling the driver.
