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Machine and Motion Control Forum
Support forum for Machine and Motion Control solutions, including Lexium MC12 and robotics, PacDrive, Modicon PLCs and I/Os, EcoStruxure Machine Expert Twin, … - from design, implementation to troubleshooting and more, by Schneider Electric
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Posted: 2025-07-06 06:14 AM . Last Modified: 2025-07-06 08:38 AM
Good Day,
After installing a device via DTM when saving the project an error message is displayed
"Object reference not set to an instance of an object".
After the above error message is received then the project is unable to be save. "Cannot save project data in Read Only mode"
Controller TM251MESE
Error occurs after adding an ATS480 starter into the project.
What is the cause of this error and how to resolve.
Thank you.
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Posted: 2025-07-06 10:24 PM
Does it work if you can remove the device again?
I guess you never saved the project then so does the project work fine every time you open it until you add this DTM?
Checked if the ATS480 DTM you have is the latest?
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Posted: 2025-07-08 09:35 PM
Good Day,
The project works fine until the DTM is added. Then the error is displayed, following that, save does not function as the file is then in "read only" mode.
Project must be closed, unsaved data lost then reopened.
I will check the on the DTM version.
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