Azbil 700 series - Adjustment Procedure When Hunting Occurs

5-3
5-1-4 AdjustmentProcedureWhenHuntingOccurs
Start adjustment
Hunting event
confirmed
Is the control loop
controller auto or manual?
Does hunting still occur
after the controller
is set to manual?
The AVP is normal.
Adjust the control
loop again.
Manually change the AVP
control parameters.
Perform the dynamic
characteristics test.
Did the hunting
phenomenon stop?
Adjustment
completed
NO
NO
Auto
Manual
YES
Perform the five-point check for the control valve to check
dynamic characteristics.
YES
Change the hysteresis, which is a control parameter for the AVP
positioner, from Light to Medium to Heavy or in the direction in which
the actuator size number decreases. (In case of the double-acting
actuator, the actuator size number increases in the reverse direction.)
<Example>
PARAM4-LIGHT → PARAM4-MEDIUM→PARAM4-HEAVY→
PARAM3-HEAVY→PARAM2-HEAVY→ PARAM1-HEAVY
If hunting still occurs after PARAM1-HEAVY is set or if you need
quick response, consult with one of our service representatives.
Figure 5.1