Delta CFP2000 Series User Manual page 698

Example: When using r to write a program
M0
If we force M0 to be 1, the frequency command will be 20.00 Hz; but when M0 is set as 0,
there will be a different situation.
Case 1: When the bit0 of Pr.09-33 is 0, and M0 is set as 0, the frequency command remains
at 20.00 Hz.
Case 2: When the bit0 of Pr.09-33 is 1, and M0 is set as 0, the frequency command changes
to 0.00 Hz.
The reason is that when the Pr.09-33 bit0 is 1 prior to the PLC scanning procedures, the
frequency will firstly revert to 0.
When the Pr.09-33 bit0 is 0, the frequency will not revert to 0.
Chapter 16 PLC Function Applications│CFP2000
FREQ K2000
16-125
K1000
K1000
END