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Figure 39: Positioner positioning behaviour
E1
Setpoint
E2
Actual value
P1
Switch-on point
P2
Switch-off point in direction OPEN
P3
Setpoint reached
X
T
Max. error (outer dead band)
Xi
1
Overrun in direction OPEN (inner dead band OPEN)
Xi
2
Overrun in direction CLOSE (inner dead band CLOSE)
Adaptive II
Contrary to adaptive positioner 1, adaptive positioner 2 will not be subject to
oscillation. The positioner detects overshooting and enlarges the inner dead band
in steps of 0.1 % until the overshooting is cancelled. After entering the idle state, the
inner dead band will be gradually reduced after a certain time (10.6 s).
8.6.3.
Overrun (inner dead band): set manually
The inner dead band determines the switch-off point of the actuator and, therefore,
influences the overrun.
The inner dead band may be set individually for the directions OPEN and CLOSE.
Manual setting is only possible if the adaptive behaviour, parameter
Adaptive
behaviour M0147
, is switched off.
Customer settings M0041
Positioner M0145
Dead band OPEN M0234
Dead band CLOSE M0235
Default values:
0.5 %
(for dead band OPEN and CLOSE)
Setting ranges:
0.0 % to 10.0 %
(for dead band OPEN and CLOSE)
Information
●
Inner dead bands may not be set wider than outer dead bands.
●
Inner dead bands may not be set too narrow as this may cause unnecessary
switching procedures (premature wear) or oscillation of the actuator.
.
8.6.4.
Max. error variable (outer dead band): set manually
The outer dead band determines the switching-on point of the actuator.
The motor starts if the actual value (input signal E2) or a change in setpoint is higher
than the maximum error variable determined by the outer dead band.
Manual setting is only possible if the adaptive behaviour, parameter
Adaptive
behaviour M0147
, is switched off.
62
Actuator controls
Application functions
ACV 01.2/ACVExC 01.2 Profibus DP