Mitsubishi Electric MELSEC iQ-R Series Programming Manual page 710

Precautions
The maximum number of digits of a real number which can be input using the engineering tool is 15, and therefore these
instructions cannot perform comparison with a real number consisting of 16 or more effective digits. When these instructions
are used to determine the match or mismatch with a real number consisting of 16 or more effective digits, the instructions
need to compare the size with the approximate values before and after the real number to be compared.
Ex.
To determine the match between E1.234567890123456+10 (16 effective digits) and a double-precision real number
ED< E1.23456789012345+10
E1.23456789012345+10
(1) Whether data in D0 to D3 are within this range is checked. (The boundary values are not included.)
Ex.
To determine the mismatch between E1.234567890123456+10 (16 effective digits) and a double-precision real number
ED<= D0 E1.23456789012345+10
ED>= D0 E1.23456789012346+10
E1.23456789012345+10
(1) Whether data in D0 to D3 are within this range is checked. (The boundary values are included.)
7 APPLICATION INSTRUCTIONS
708
7.9 Real Number Instructions
D0 ED< D0 E1.23456789012346+10
E1.234567890123456+10 E1.23456789012346+10
(1)
E1.234567890123456+10 E1.23456789012346+10
(1)
Y10
Y20