Mitsubishi Electric FR - F700 Programming Manual page 171

Basic instructions (32-bit)
CAUTION
The comparison instruction regards the specified data as BIN values. Hence, if the value
whose most significant bit (b31) is 1 (8 to F) is specified for comparison of hexadecimal
data, it is regarded as a negative BIN value.
Example
Comparison of 8-digit HEX values
D> H8000 H0000 H7FFFHFFFF
Regarded
as -2147483648
in BIN.
Therefore, the result is -2147483648 < 2147483647 and Y10 does not turn on.
164
Y10
Regarded
as 2147483647
in BIN.