Siemens 6DR55 Series Manual page 106

Operation
31.DEBA
32.YA
33.YE
.
34.YNRM
104
Dead zone of the controller
At dEbA = AUto the dead zone in automatic operation is adapted
continuously to the requirements of the control circuit. The dead zone is
gradually increased on detecting a control oscillation. The reverse
adaptation 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 61 and 62)
and
Manipulated variable limiting end (see figure 61 and 62)
With the parameters "YA" and "YE" the mechanical actuating distance
(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.
NOTE
YE must always be set to greater than YA.
Manipulated variable standardization (see figure 61 and 62)
With limiting of the manipulated variable (by "32.YA" and "33.YE") two
different scalings are produced for the display and the position
feedback via the current output (MPOS or FLOW).
The MPOS scaling shows the mechanical position (0 to 100 %)
between the hard stops of the initialization. This is not affected by the
parameters "32.YA" and "33.YE". The parameters "32.YA" and "33.YE"
are displayed in the MPOS--scale.
The FLOW--scale is the standardization (0 to 100 %) to the range
between "32.YA" and "33.YE". The setpoint w (0 to 100 %) is always
referred 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
appropriate scale on the display.
SIPART PS2 PA Manual
A5E00127926--05