Manual 37259C
SPM-D11 - Synchronizing Unit
5.
Controller operated as a P-only controller
(where T
n
=
∞
[screen setting: T
n
=0], T
V
= 0).
6.
Increase gain K
P
(P gain) until the control loop oscillates continuously at K
P
= K
Pcrit
.
CAUTION
If the control starts to oscillate uncontrollably, perform an emergency shutdown and change the
screen setting accordingly.
7.
Measuring of the cycle duration T
crit
8.
Set the parameters:
PID controller
PI controller
K
P
= 0,6
× K
Pcrit
K
P
= 0,45 × K
Pcrit
T
n
= 0,5
× T
crit
T
n
= 0,83 × T
crit
T
V
= 0,125 × T
crit
Step response
Controller setting
Optimum (x
m
≤
10 %)
Controller setting
T
crit
Controller setting
Incorrect
0
1
x
0
t/s
0
0
1
x
t/s
0
1
x
0
t/s
Figure 4-3: Step response - controller set-up
---
Pr.-sensitivity
Kp = 000
P gain
(K
P
) Proportional-action coefficient
1 to 240
The proportional-action coefficient K
P
indicates the closed-loop control system
gain. By increasing the gain, the response is increased to permit larger corrections
to the variable to be controlled. The optimum setting depends on the behavior of
the system. If the gain is too low, the control action becomes slow. If the gain is
configured too high, the result is excessive overshoot/undershoot of the desired
value.
---
Reset time
Tn = 00.0s
Reset time
(T
n
)
0.2 to 60.0 s
The reset time T
n
represents the I-component of the PID controller. The reset time
corrects for any offset (between set point and process variable) over time until the
process variable and the set point are the same. This parameter defines how quickly
the reset attempts to correct for any offset. If T
n
is configured as 0.00 s, the I-
component of the PID loop is disabled.
---
Derivative act.
time Tv=0.00s
Derivative-action time
(T
V
)
0.00 to 6.00 s
The derivative-action time T
V
represents the D-component of the PID controller.
The D-component of the controller output becomes effective with large variations
of the offset, e.g. in case of load-shedding. The lower the derivative-action time is
configured, the higher the controller reaction is. If T
V
is configured as 0.00 s, the
D-component of the PID loop is disabled.
© Woodward
Page 31/79
