Request for Assistance with Online Logic Changes in PLC System using Codesys

Dear Sir,

We are writing to seek guidance regarding our current situation with the Opto 22 Groov EPIC PR1 PLC system. Over the past year, we have successfully downloaded and implemented logic using Codesys, and the PLC has been operational without issues.

However, we now require minor modifications to the logic. Despite attempting to upload the modified logic, we are unable to see the “online change” option, prompting us to consider a direct logic download.

Our concern is that during this process, certain digital outputs or analog outputs might momentarily disrupt operations, which is unacceptable given the system’s continuous 24x7 operation. We have explored online changes in other PLC systems, but due to the absence of the last downloaded backup, we are unable to proceed confidently.

There are different factors that can require a full download vs an online edit, but it appears that this project had been downloaded to a different controller at some point:
I would recommend that you store the source for each controller onto the controller itself to avoid these issues in the future. Then the source you grab will have only been used with that particular controller.

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Oh man, I feel your pain and have been there.

If you can find the download information files from the original PC that did the download, that would hopefully allow for the online change. You just need to put them in the same folder as the .project file.

To build on @greichert’s comment, I highly recommend enabling the “Source Download” feature in Project Settings. This will prompt you to download the source anytime you download to the controller.