Preventive actions for error code “C153 Protective Stop: joint positions deviates from path”
Concerning software versions:
Examples are valid for:
CB3 Software version: 3.1.1804 and later
e-Series Software version: All versions
Note that older or newer software versions may behave differently.
Incorrect installation and programming settings, high accelerations with sudden change of trajectory or if robot is running close to it’s performance limit can cause these stops, as an indication that the force safety setting has been exceeded.
What can be checked by you to troubleshoot the stops?
- Check installation settings and make sure the following settings are inputted correct:
- Tool Center Point
- Center of Gravity (center of weight for the end-effector)
- Check safety settings and verify if settings are correct according to the risk assessment on the application.
- Verify that the robot does not push excessively in pick-up place positions, thereby creating unwanted forces that can cause protective stops. Re-teach relevant waypoints for higher precision.
- As a way of troubleshooting, reduce force limit in safety settings to find motions in the program that are close to protective stops. Once these motions are identified, reduce speeds and/or accelerations accordingly and set force limits back to original settings.
- If risk assessment allows it, the force limit in the safety settings can be increased. Try increasing in steps of 5N until issue is resolved. No more than 25N should be necessary to resolve it.
- If a very hard or multiple collisions has occurred, it highlig recommended to check if any of the joints has become loose. Check Service Manual for Inspection Plan.
- If waypoints has start shifting/moving and need to be re-taught and protective stop is increasing, it could be a joint has become loose. Check Service Manual for Inspection Plan.
If you have no success with above guidelines, please contact the Distributor from where the robot has been purchased in order to get additional help.
Prior to contact, kindly make sure to provide the following:
- Description of application and where the protective stop occurs.
- Videos and pictures of application, specially of end-effector.
- Backup of programs and installation file
- Backup of log history and crash report