Samson Series 420, Руководство пользователя

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10 EB 7500 EN
Start-up and settings
4 Start-up and settings
Before start-up of the control loop, check all
devices to make sure that they are connected
correctly, do not leak, and function properly.
Release lock (7) and pull out the plug-in unit
of the compact controller station for easier
access to the operating controls at the con-
troller.
Check the turnboard to make sure the correct
direction of action is set at the controller (see
section 3.1.1). Set arrow symbol (6) for
valve position at 100 % signal pressure ac-
cordingly:
Arrow symbol facing:
Upward : valve OPEN
Downward : valve CLOSED
4.1 Tuning the controller
The controller needs to be tuned to the char-
acteristics of the controlled system using the
Kp and Tn and/or Tv adjusters at the control-
ler module (Fig. 1) to ensure that the control-
ler can keep any system deviations for all set
points caused by the disturbance variables to
zero or at least minimize them.
The tuning test following the Ziegler and
Nichols method is a simple way to tune the
controller. In this method, the controller runs
in closed-loop operation with P action to the
point where it is still stable. It can only be
applied to controlled systems in which the
controlled variable can be made to hunt.
1. Set manual/automatic switch (10) to
manual . Apply supply pressure
(1.4 ±0.1 bar) to Z.
2. Set the proportional-action coefficient Kp
to a low value (0.2) at the comparator.
PI and PID controllers only: set Tn restric-
tor to its maximum value (50 min) and Tv
to its lowest value (0.01 min).
3. Adjust the set point at the top rotary
knob (11) until the green pointer (2)
points to the required value on the scale.
PI and PID controllers:
4. Adjust the manual output yH at the bot-
tom rotary knob (9) to start up the con-
trol loop until the controlled variable in-
dicated by the red pointer (3) slowly ap-
proaches the adjusted set point (green
pointer).
Fig. 3: Front view
1 Front panel
2 Set point pointer
3 Controlled variable
pointer
4 Control signal yA
5 Control signal yH
6 Valve CLOSED/OPEN
7 Lock
8 LED
9 Manual adjuster for yH
10 Manual/automatic
switchover
11 Set point adjuster
12 Label
2
4
3
5
1
12
10
11
9
7
8
6