Error: String is too long for the controller

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Hi every one, i am try to use the COGNEX CAMERA 7802 to guide the UR3 robot for pick and place application, when running sometime this error happen, could anyone help me to solve it?

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1946×2048 481 KB

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Hi Dylan,

It looks like it doesn’t want to process the string because of a character limit somewhere.

You could try to get rid of some decimals in your vision job using the FormatString function:

image
image1178×1014 117 KB

This will limit the number of decimals to a maximum of 6 which saves you a lot of characters.

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Thanks a lot, i fixed it with your help.
by the way, my robot always does not go to the correct point to pick , i have to offset in the insight software. do you have any ideal for this problem?

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That is probably a calibration issue. How did you do your calibration?

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I calibration follow this guide
EasyBuilder Help - Connect to the Vision System and Perform Hand-Eye Calibration - Documentation | Cognex

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I can’t tell exactly why it does what it does but here are a few things that might lead to this problem:

  • Lens distortion. If you have a cheap lens with a lot of distortion this might lead to calibration issues. You could try to solve this by undistorting the image.
  • Moving the robot to 3 different points and using that as input for a calibration is prone to errors. If these points are approximations this will lead to undesirable result. Maybe calibrating using a calibration grid might help here. The benefit is that you will get a good conversion from pixels to mm, and you only need to calculate the offset once between the camera and robot.
  • To be sure, please check if the camera is triggered properly. If not you might get the same coordinates again.

Can you explain in a few sentences how you perform the calibration?

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