That might give you some answers for what you need to look for on the new Kunbus device. But it depends on how they added retain data and I don't know enough to do or say more than link to the above driver.
You can also purchase a service ticket on the store, as unhelpful as that is for me to say.
Last edit: Morberis 2020-11-30
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Kunbus has a new device named RevPi Compact. This controller has NVRAM accessed through the file path /sys/bus/nvmem/devices/1-00500/nvmem
How do I configure CodeSys to use this NVRAM for Persistent memory variables?
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I would propose to ask Kunbus...
That is where I started, but they are not Codesys experts.
I don't think this will be a trivial task. But take a look how retain data was added with a I2C MCP7941x chip.
That might give you some answers for what you need to look for on the new Kunbus device. But it depends on how they added retain data and I don't know enough to do or say more than link to the above driver.
You can also purchase a service ticket on the store, as unhelpful as that is for me to say.
Last edit: Morberis 2020-11-30