Mitsubishi Q series...why is 2.5 rounded to 3?

parky said:

K25 is not 2.5 as it is an integer, it is 25, I think you will find that the rung contains a contact that moves the K25 into that register. As I cannot see what logic is before that puts the data into those registers. You will probably find that the register is being modified elsewhere putting 3 into it (or from the HMI) and the logic (we cannot see) is putting default values i.e. 25 into it on some sort of basis) i.e. perhaps default values on a key press etc.

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parky said:

That's what I thought, remember, moving values into a register requires a "TRUE" rung so the M72 must be true before it will transfer. again think about what context the type values are in Mitsubishi "K" is integer (only whole numbers), "E" is floating point, "H" is hexadecimal.

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parky said:

No, if you do that a number of things will happen, according to the logic you posted D331 is an integer so putting E2.5 into it will also write to D332 and probably destroy some other data used elsewhere, D331 is probably only used as an integer and will probably stop the PLC on an error.
You cannot write float values to integer registers. It is obvious that it has to be a whole number floating point values do not conform to integers.
Also you will not see M72 trigger as it is reset immediately after being true so is only valid for the time between the start of that rung and the rung that resets it, however, it should be putting 25 into the register unless it is being written to elsewhere.

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