Mitsubishi Electric MELSEC Q Series Structured Programming Manual page 55

(3) Precautions for when setting input values of single-precision real data/double-precision real
data from the programming tool
(a) Single-precision real
Single-precision real data are processed as 32-bit single precision in the programming
tool, and thus the number of significant figures becomes approximately 7. If the input
value of single-precision real data exceeds 7 digits, the 8th digit is rounded.
If the value after the rounding exceeds a value between -2147483648 and 2147483647,
an operation error occurs.
Example 1: When '2147483647' is set for the input value
Example 2: When 'E1.1754943562' is set for the input value
(b) Double-precision real
Double-precision real data are processed as 64-bit double precision in the programming
tool, and thus the number of significant figures becomes approximately 15. If the input
value of double-precision real data exceeds 15 digits, the 16th digit is rounded.
If the value after the rounding exceeds a value between -2147483648 and 2147483647,
an operation error occurs.
Example 1: When '2147483646.12345678' is set for the input value
Example 2: When 'E1.7976931348623157+307' is set for the input value
8th digit '6' is rounded.
The value is handled as '2147484000'.
8th digit '3' is rounded.
The value is handled as 'E1.175494'.
16th digit '6' is rounded.
The value is handled as '2147483646.12346'.
16th digit '5' is rounded.
The value is handled as 'E1.79769313486232+307'.
4.4 Method for Specifying Data
4.4.4 Single-precision real/double-precision real data
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