Mitsubishi Electric MELSEC iQ-R Series Programming Manual page 236

Operation error
Error code Description
(SD0)
2821H The device ranges starting from the ones specified by (s1) and (d) are overlapping.
The device ranges starting from the ones specified by (s2) and (d) are overlapping.
When bits of a word device are specified, the bits other than the specified ones for storing the operation result
do not change.
D10.F
0
D10.F
0
6 BASIC INSTRUCTIONS
234
6.1 Comparison Operation Instructions
0 1 0 1 1 1 1 1
0 1 0 1 1 0 0 0
D10.0
0 0 1 1 0 0 0
D10.0
0 1 1 1 0 0 0