That’s true. It won’t happen for OH2 now.
It’s hard to see how useful 64-bit floats really are outside of astronomy!
We’ve not really dealt with this before, a previous look died due to no follow up.
should be possible to get two uint32 from Modbus binding, and reassemble into the 64-bit image. Quite how you persuade java to take that as a double type I’m not sure.
Before you get that far, you’d need to determine what order the Alfen thingy puts the registers in.