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Chapter 7. PARAMETER SETUP
7-16
● M .-C (motor control method selection)
0: MFB control (conventional) + estimated position control
1: MFB control (conventional) only
2: Estimated position control only
• 0: MFB control (conventional) + estimated position control
• When MFB (Motor Feed Back) input is normal, the motor position is controlled by the
actually measured MFB.
• When MFB input is in error, the motor position is controlled by an estimated MFB
value. This state is referred to as “estimated position control state.”
For example, when the motor rotates at a position where the feedback potentiometer
has deteriorated, MFB input changes suddenly. This sudden change is detected as an
error, and the correct MFB position is estimated. The motor position is also controlled
by the estimated MFB value when the MFB disconnected alarm has occurred.
• In the estimated position control state, an error will inevitably occur between the actual
motor valve opening and estimated MFB value.
So, set the closed-side relay to ON at all times when output (MV) ≤ 0.0%, and the
open-side relay to ON at all times when MV ≥ 100.0% to set the motor to a fully-open
or fully-closed state to compensate this error.
However, note that this error is not compensated when MV is limited to within 0.1 to
99.9% by the output limitter, or when MV is 0.0% or less or 100% or more due to the
control state.
• The following are probable causes when estimated position control is likely to be car-
ried out:
- Defective motor valve opening adjustment
- Deteriorated feedback potentiometer, insufficient resolution
- Defective MFB wiring.
• 1: MFB control (conventional) only
• When this setting is used, conventional MFB control is carried out. When the MFB
disconnected alarm occurs, the MFB value is regarded as 150.0%, and the closed-side
relay is ON at all times.
• 2: Estimated position control only
• When this setting is used, control is in the estimated position control state at all times,
and the motor position is controlled by the estimated MFB value regardless of the state
of MFB wiring.
• When this setting is used, enter the correct M .-t item.
• The MFB disconnected alarm does not occur.
• The error between actual motor valve opening and estimated MFB value is compen-
sated by forcibly continuing motor operation in the closed or open directions when MV
is 0.0% and 100%.