Cashco Siemens PS2 I/P - Manual (Page 84)

Operation
84
SIPART PS2 Manual
A5E00074631-01
Setpoint vertex points (see figure 4-8, page 83)
A flow parameter can be assigned to the respective setpoint vertex va-
lue at an interval of 5%. These points lead to a polygon chain with 20
straight lines which therefore represents a projection of the valve cha-
racteristic.
The setpoint vertex values can only be input at You may only enter a
strictly monotonous characteristic, the vertex values of which differ by
at least 0.2%. If the monotony condition has been infringed, an error
message appears as soon as you want to exit ”Configuration”. If you
need a falling characteristic you have to enter a rising characteristic
and reverse the direction of action by entering 7.SDIR = fall.
Dead zone of the controller
At dEbA = AUto the dead zone in automatic operation is adapted conti-
nuously to the requirements of the control circuit. The dead zone is gra-
dually increased on detecting a control oscillation. The reverse adapta-
tion takes place by a time criterion.
In the other discrete settings the fixed value is used for the dead zone.
Manipulated variable limiting start (see figure 4-8 and 4-9)
and
Manipulated variable limiting end (see figure 4-8 and 4-9)
With the parameters “35.YA” and “36.YE” the mechanical actuating di-
stance (from stop to stop) is limited to the set values. In this way the
mechanical setting range of the actuator can be limited to the active
flow and the integral saturation of the commanding controller avoided.
Manipulated variable standardization (see figure 4-8 and 4-9)
With limiting of the manipulated variable (by “35.YA” and “36.YE”) two
different scalings are produced for the display and the position feed-
back via the current output (MPOS or FLOW).
The MPOS scaling shows the mechanical position (0 to 100%) bet-
ween the hard stops of the initialization. This is not affected by the pa-
rameters “35.YA” and “36.YE”. The parameters “35.YA” and “36.YE”
are displayed in the MPOS-scale.
The FLOW-scale is the standardization (0 to 100%) to the range bet-
ween “35.YA” and “36.YE”. The setpoint w (0 to 100%) is always refer-
red to this range. This gives (also by using valve characteristics) a
quasi--flow--proportional display and position feedback Iy.
To calculate the control difference, the setpoint is also shown in the ap-
propriate scale on the display.
13.SL0 to 33.SL20
34.DEBA
35.YA
36.YE
37.YNRM