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Chapter 4. Functions
If MFB AT ends and the "Auto-tuning" setting changes to 3 (Auto-tuning has been
completed), the settings for "Fully closed MFB count," "Fully open MFB count," and
"Full opening time" are completed.
Handling Precautions
•
If "Control method selection" is set to 0 or 1, the settings for "Fully closed MFB
count," "Fully open MFB count," and "Full opening time" are used.
•
If "Control method selection" is set to 2 or 3, the setting for "Full opening time"
is used. Because MFB AT cannot be executed, manually set "Full opening time"
from the display unit.
z
Dead zone
The setting is valid if a MOTOR block is inserted (using four slots) into the I/O slot.
The dead zone of the motor drive output can be set.
Item (bank)
Display
Description
Initial value
Dead zone
PP (position proportional) bank
MENU > PP
Dead zone
0.5000 to 25.000 %
10.000
This sets the dead zone for the MFB opening where the motor drive output CLOSE-
side relay turns on and the MFB opening where the motor drive output OPEN-side
relay turn on.
Set the initial value by taking into consideration the controllability and lifespan,
using 10 % as a general guide.
If the dead zone is small, MFB opening follow-up control with respect to the output
value (such as MV) is improved, but the motor drive output ON/OFF frequency
is increased, which can shorten the lifespans of the motor and motor drive output
relay. On the other hand, if the dead zone is large, the lifespan is extended, but
controllability is reduced.
The minimum value of the dead zone is the value where the motor open/close
operation stops hunting while the dead zone settings are being changed at a
constant output value in MANUAL mode or similar. If set at the minimum value,
the lifespans of the motor and motor drive output relay will be extremely shortened,
so set to a value larger than the minimum value by adding a safety margin.
Dead zone
*1/4 of dead zone set value
*
*
OPEN relay ON
CLOSE relay ON
Output (%)
MFB opening (%)
Handling Precautions
•
If "Control method selection" is set to 0 or 1, set "Dead zone" after executing
MFB AT (MFB auto-tuning).
•
If "Control method selection" is set to 2 or 3, set "Dead zone" after setting "Full
opening time."