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Troubleshooting PLC Program Not Transitioning to RUN Mode

Question:

Hello everyone, I'm currently facing a challenge and would appreciate some assistance. After updating my PLC program and transferring it to my controller, I encountered a problem when trying to run the program. Despite a successful download, the PLC remains in "STOP" mode and doesn't transition to "RUN" mode. I have a Allen-Bradley CompactLogix 1769-L24ER PLC and used Studio 5000 Logix Designer for the update. The changes I made include adding a new subroutine for additional sensor readings and some timer instructions. I have carefully reviewed the program for errors or typos and ensured all safety interlocks and necessary conditions are in place. Have you experienced a similar issue before? Could there be a hardware problem that I'm overlooking? Any insights or suggestions would be immensely helpful. Thank you in advance. Elena

Top Replies

To ensure proper functioning, verify that the keyswitch is positioned in the RUN or REMOTE mode under the memory card cover. Detailed instructions can be found on page 39 of the Rockwell Automation manual: https://literature.rockwellautomation.com/idc/groups/literature/documents/um/1769-um011_-en-p.pdf.

Attention Studio 5000 Logix Designer users! A product notice has been issued regarding a potential anomaly with versions V31 through V35 of the software. After downloading ladder diagram routines to certain controllers, such as ControlLogix 5580 and CompactLogix 5380, the routines may stop execution. The issue can be resolved by updating to software versions V33.02 and V34.02. For more detailed information and corrective measures, refer to Knowledgebase IDPN1620/1139086. Stay informed and keep your software up to date for optimal performance.

Aardwizz has announced a product notice regarding potential issues with Studio 5000 Logix Designer V31 through V35 Ladder Diagram Routines where execution may halt after downloading. It appears that the 1769 series is not affected by this notice. Click to learn more.

Can you clarify the concept of "stop" mode and whether it is indicated by a red fault signal?

In a forum discussion, jstolaruk noted that the 1769 series may not be covered in the product notice. Following their observation, another user suggested trying a possible fix based on personal experience with a similar issue. The suggestion involved switching the keyswitch to RUN mode from REM and power-cycling the PLC, as this workaround had worked on a different processor. It's worth a try for the original poster facing the problem, as sometimes the keyswitch commands may not always be followed accurately by the processor.

More Replies

Hello everyone, I am currently facing a problem with my Allen-Bradley CompactLogix 1769-L24E PLC after updating the program using Studio 5000 Logix Designer. Despite ensuring all safety interlocks are in place, the PLC remains stuck in "STOP" mode and won't transition to "RUN" mode. I added a new subroutine for sensor readings and timer instructions, checked for errors or typos, and confirmed all necessary conditions are met. Has anyone encountered a similar issue before? Could this be a hardware problem? I appreciate any insights or suggestions. Thank you. Elena.

Aardwizz has issued a Product Notice (2023-04-002) regarding a potential issue with Studio 5000 Logix Designer software. Users of versions V31 through V35 may experience interruptions in ladder diagram routines after downloading. The notice has been updated to specify the affected versions and announce the release of software versions V33.02 and V34.02 to address the issue. For more information on this anomaly and corrective measures, refer to knowledgebase IDPN1620/1139086. Your understanding and cooperation regarding this matter are greatly appreciated. Elena

Frequently Asked Questions (FAQ)

FAQ: 1. Why is my PLC program not transitioning to RUN mode after a successful download?

Answer: Answer: There could be several reasons for this issue, such as errors in the program logic, safety interlocks not being satisfied, hardware problems, or incorrect configuration settings.

FAQ: 2. How can I troubleshoot a PLC program that remains in STOP mode on an Allen-Bradley CompactLogix 1769-L24ER PLC?

Answer: Answer: You can start by checking the program logic for errors or typos, ensuring all safety interlocks and necessary conditions are met, verifying the configuration settings, and inspecting the hardware for any potential issues.

FAQ: 3. What steps should I take if I added a new subroutine and timer instructions to my PLC program, but it still won't transition to RUN mode?

Answer: Answer: Double-check the newly added subroutine and timer instructions for correctness, review the interaction with existing program elements, and verify that the program as a whole is structured correctly and meets the required conditions for transitioning to RUN mode.

FAQ: 4. Are there common troubleshooting strategies for resolving a PLC program that won't switch to RUN mode in Studio 5000 Logix Designer?

Answer: Answer: Yes, common strategies include thorough program inspection, debugging for errors, ensuring proper program organization, checking for conflicts with existing logic, validating hardware connections, and verifying that all necessary conditions for transitioning to RUN mode are satisfied.

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