Mitsubishi Electric MELSEC iQ-R Series Programming Manual page 1434

Precautions
If the sequence is stopped while SM325 is off, coil HOLD steps become inactive. The sequence cannot be restarted with the
hold status. If the sequence is stopped while SM325 is on, the sequence can be restarted with the hold status.
Operation error
Error code Description
(SD0)
31A1H The specified block does not exist.
The instruction is executed when no SFC program (scan execution type) exists or SM321 is off.
31A2H The specified block No. is out of the range, 0 to 319.
13 SFC PROGRAM INSTRUCTIONS
1432
13.1 SFC Control Instructions