New user asking about PLC download issues
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I had been using DCS all along; now I have a redundant 400 system. I noticed an issue with the logic, so I went to modify it. After making the changes, I tried to download it from the project, but I got an error message stating that the hardware configuration was inconsistent. Consider whether the open project does not match the device online, which is why it was not downloaded. I found a program that seemed older elsewhere, but its filename indicated it was the final version; so I modified the logic and tried to download the project. It was indicated that two CPUs were available, but it wasn’t clear which CPU should be used, and with such unclear instructions I decided to cancel the download. After much thought, I opened the modified FC and selected PLC ----- Download in the menu; a completion message was displayed. I can’t believe it’s over in just 1 second; it’s hard to believe. The logic for detecting online play has also been changed; I’m not sure if this kind of download is correct Do I have the modified program for both redundant controllers? ? Please ask an expert to help analyze it!
Clicking download on FC involves only minor modifications, which is quite appropriate. Clicking ‘Download’ in the menu bar usually means downloading the entire file; special attention should be paid to this, as online downloads generally don’t work this way.
When you click download in the project, it should download everything as a whole, including the hardware configuration. It’s possible that the hardware configuration has been altered, resulting in inconsistencies; it’s best to check where those discrepancies lie, otherwise it will cause problems in the future. Typically, Siemens downloads the hardware configuration and program blocks separately; for the hardware configuration, it is necessary to carefully read the instructions to determine whether it can be installed offline. Program blocks also need to be classified; functional blocks generally present no issues, but caution is required when it comes to download blocks. As for redundancy, I remember that the two CPUs need to be downloaded separately; there should be a function to check whether the programs in the two CPUs are identical. Take a look.
One more thing: the version that is stored may not be reliable. It’s better to upload the source code first; if there are comments, they can be imported separately and then modifications can be made based on that. Otherwise, identifying the differences will be a hassle.
Do I also need to download FC using two separate redundant controllers? In practice, when I install FC, there’s no guidance on how to import comments and symbols after installing the program on two CPUs. I’m a beginner; are there any resources recommended on this topic? I want to learn about it*
This post was last edited by myface on 2018-7-7 08:41. I can’t remember exactly how to download it; I haven’t used it for several years now, and once you stop using something, you forget how to do it. Siemens has an enormous number of teaching materials; just the official documents alone are too much to go through. You can take a look at this first using Step7.
The backup PLC can be powered off first, the main PLC can be installed, and then it can be turned on again to synchronize.
If a redundant system has been established, it is sufficient to download just one copy, and it should be downloaded to the main CPU. When in online mode, only IO cards will be visible under the main CPU; none will be shown under the secondary CPU. I remember it was like that.