I was wondering if it is possible to retain the values of the ctrlX IO modules. When ever I do a download of my PLC program the IO of the modules (in this case the XI211116 module) are resetted. I would like to keep the values before the download also during and after the download. is this possible?
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Could you tell us some more about your usecase why and when do you need such function? At the moment there is no solutions for keeping the IO output values alive over the complete download cycle. You would need to use the online change for that.
As a workaround you could use PLC system events to save your actual IO data to a retain variable e.g. PrepareStop and then use another system event e.g. PrepareStart to restore it. Beware that here a short time with IOs getting to FALSE cannot be avoided.
Please also beware that there is a function called substitute for keeping IO values in actual state when fieldbus goes down to INIT. This is available for the S20-DO, but not for ctrlX IO XI2... (only fix fallback value). Substitute is also available for analog outputs S20 / ctrlX IO. See S20 documentation here.
This would be of interest to us in the test phase of a project. This is because we have a lot of Electrolysers(ELs) and other devices hanging behind a relay. This relay has to be controlled by means of the IO cards. During the testing of the ELs, the PLC project has to be tested/adjusted several times which means that all ELs go off and then have to be restarted. This is time consuming and does not fall under desired use of the ELs.
I am looking in the documentiation of the ctrlX IO but i couldn't find anything regarding substitute?
It is only available for outputs and the documentation is still in preparation. Sorry for the misunderstanding, I corrected my post.
I also talked to our R&D and our PLC supplier and am afraid to say that making IOs persistent is not possible and not planned to be.
Is there a reason why online change is not used for your test cases? Like mentioned above this does not have interference with the IOs.