How to Fix the KUKA Program Selection Not Permissible Error in KUKA RobotsKUKA robots are widely used in industrial automation for tasks ranging from welding to assembly and material handling. While they are highly efficient and reliable, users occasionally encounter issues that can interrupt workflows. One common issue is the Program Selection Not Permissible error. This problem can be confusing, especially for new operators or technicians, but it usually has a straightforward solution.
This topic will explain what the error means, why it happens, and how to resolve it step by step. Whether you’re using a KUKA KRC4 controller or working with older models, the information here will help restore normal operation quickly.
What Does Program Selection Not Permissible Mean?
The error message Program Selection Not Permissible typically appears on the KUKA smartPAD when you try to select or start a program, but the system blocks the action.
This message means that, under the current system conditions or mode, you are not allowed to select or start a robot program. It’s a protective feature designed to ensure that only permitted actions are taken during certain robot states.
Common Situations When This Error Appears
Understanding when and why this error occurs is the first step to fixing it. Here are the most common scenarios
1. Wrong Operating Mode Selected
KUKA robots have multiple operating modes T1 (manual slow), T2 (manual fast), AUT (automatic), and EXT (external). Some modes restrict certain actions. For example, you cannot select a program in EXT mode from the smartPAD.
2. External Control Is Active
If the robot is in EXT mode and controlled via PLC or another external controller, local program selection is blocked to prevent conflicts.
3. User Group Restrictions
KUKA systems can be configured with different user levels. If you’re logged in as a basic user, you may not have permission to select or start certain programs.
4. Safety Circuit Not Ready
If safety conditions like the emergency stop, enabling switch, or protective door are not met, the controller will not allow program selection.
5. Incorrect Submit Interpreter State
KUKA systems run a background task called Submit Interpreter (SPS.SUB). If this program is not running correctly or is stuck, the robot may reject program selection.
Step-by-Step Guide to Resolve the Error
Here’s how you can troubleshoot and resolve the Program Selection Not Permissible error
Step 1 Check Operating Mode
Make sure the robot is in an appropriate operating mode for manual program selection. Use T1 or T2 mode on the smartPAD to select and test-run programs manually.
To change the mode
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Press the mode selector button on the smartPAD.
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Choose T1 or T2, depending on your requirement.
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Confirm the change.
Step 2 Verify Login Level
Some KUKA configurations restrict program control to certain user levels. Check your current login level
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Go to the login menu.
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Log in as Expert or Administrator if available.
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Try selecting the program again.
Be cautious with higher permission levels, as changes made can impact safety and performance.
Step 3 Inspect Safety Conditions
Ensure that all safety conditions are satisfied
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Emergency stop button is released.
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Protective doors are closed.
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Operator enabling switch is pressed if required.
If the robot is in a cell with light curtains or safety gates, verify that all sensors report safe status.
Step 4 Restart Submit Interpreter
If the Submit Interpreter is not running or stuck, restart it
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Navigate to the Display > Submit Interpreter menu.
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Stop and then restart the Submit Interpreter.
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Wait a few seconds and try selecting your program again.
Ensure the SPS.SUB file is not corrupted or misconfigured.
Step 5 Switch from EXT to AUT or T1
If your robot is set to EXT (external) mode, you cannot select a program using the smartPAD. You must switch to AUT or T1
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Turn the mode selector to AUT or T1.
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Once in the correct mode, select your program from the file browser.
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Press the green start button to begin execution.
If your system must remain in EXT mode, then the program must be selected via the external controller (PLC or automation software).
Preventing the Error in the Future
Once resolved, it’s important to prevent this issue from reoccurring. Here are some preventive tips
Configure User Roles Carefully
Limit what each user level can do, but ensure operators have enough access to perform daily tasks without constant administrative intervention.
Train Personnel on Operating Modes
Make sure operators understand the implications of each operating mode. Most issues occur when the robot is unintentionally left in EXT mode.
Monitor the Submit Interpreter
Regularly check the health of SPS.SUB. If you modify this program, always test it thoroughly in T1 mode before using it in production.
Establish a Safe Startup Routine
Create a checklist that includes confirming safety circuits, selecting the correct mode, and logging in with the correct user level before beginning operations.
When to Seek Technical Support
If none of the steps above solve the issue, you might be facing a deeper system configuration problem or software error. Consider contacting your KUKA support partner if
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The error persists after multiple reboots.
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You cannot switch modes.
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The smartPAD displays additional system errors.
Before calling support, gather logs, screenshots, and version numbers to help speed up diagnostics.
The KUKA Program Selection Not Permissible error may seem serious at first, but it’s often the result of a simple misconfiguration or system state. Most of the time, switching to the correct operating mode, verifying user permissions, or resolving safety issues will clear the error.
By understanding how KUKA’s control logic works and following structured troubleshooting steps, you can keep your automation systems running smoothly with minimal downtime.
Would you be interested in an topic covering common smartPAD interface issues or how to manage KUKA projects with WorkVisual?