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How to select CoaXPress cables for machine vision and multi-camera systems

Posted by Gretchen Alper on Tue, Oct 4, 2016

The continued adoption of CoaXPress in machine vision inspection and metrology systems is partially due to the higher video data rates enabled.  But in multi-camera systems, the smaller more flexible cables are an advantage to fit in tight spaces and enable moving heads. 

coaxpress-cables-multi-camera.png

For many CoaXPress imaging systems, the cable selection can be relatively simple.  For others where a very long cable length is required, or there is a constantly moving imaging head (as common with multi-camera systems, such as with AOI), cable selection is more challenging.

So the first step with cable selection is to consider these 3 requirements:

  • The speed configuration
  • Cable length
  • Cable flexibility

 

Frame speed over cables:

For details on the different frame speeds or bit rates over CoaXPress cables:

Several Versions of CoaXPress to Meet Different Machine Vision Requirements

 

Cable Length:

One of the advantages of CoaXPress over other interface standards such as Camera Link and USB 3.0, longer cable lengths (i.e. 7 meters) can be used without repeaters which effect signal integrity.  For most machine vision systems, longer lengths are not required. 

CoaXPress certified cables can be verified by checking for the label with the logo (see image below):

CXP-compliance-cable-logo.png 

 

Cable Flexibility:

What is of more concern is the flexibility of the cables required.  If the wrong cable is selected, there could be failures.  One problem is that there is no standard definition of high flex cables. 

 

The cable supplier can provide data/reference numbers on the following:

  1. Flex test
  2. Twisting test
  3. U-shape bending test
  4. Moved bending test
  5. Cable bear bending test

 

If a highly durable, high flex cable is required, we recommend acquiring some samples and testing them under the system conditions.  Within the CoaXPress protocol, there is a link test to check the data between the camera and frame grabber for errors.  This is called the Bit Error Rate Testing and can help you verify the cable selection.

 

Contact us with any questions or for a free application note on using the Bit Error Rate Testing with the Euresys CoaXlink frame grabbers.

 

Related Posts:

More CoaXPress frame grabber options and other accessories to enable fastest data rates

 

Multiple CoaXPress IP core providers eases integration for further adoption

 

Moving from Camera Link to CoaXPress – the simplicity of CoaXPress

 

 

Topics: Interface Technology

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