Omron C200HX Operation Manual page 311

Subroutines and Interrupt Control
Interrupting Writing Multiple Words of Data
Flow of Processing
When the interrupt occurs while processing ADD, the addition result, 1235, is
saved temporarily in memory and not stored in DM 0000. Although #0010 is
moved to DM 0000 in the interrupt program, the addition result that was saved is
written to DM 0000 as soon as processing returns to the main program, effec-
tively undoing the results of the interrupt program.
Countermeasure for Above Problem
Section 5-23
293