Burkert Type 8635 - Manual (Page 22)

20 - 8635
S
YSTEM
D
ESCRIPTION
(S/HART)
If the SIDE Control (S/HART) is operated as a process controller, the abovementioned position control
becomes a lower-ranking auxiliary control loop. The overall result is a cascade control system.
The process controller (as a main control loop) is implemented in the SIDE Control (S/HART as a PID
controller. In this case the process setpoint (SP) is preset and compared with the actual value (PV) of
the process variable to be controlled, which is supplied by a sensor. Formation of the correcting variable
is done according to the description of the positioner. Z2 represents a disturbance acting on the
process.
Operation as a process controller (S/HART, option)
Characteristic of the process controller software (option)
Supplementary function Effect
Positioner with supplementary functions
AUTOTUNE
Automatic adaptation of positioner to the control valve
in use.
Tight-closing function
Valve closes tight outside the control range. A value is
specified (in %) from which the actuator is completely
exhausted (at 0 %) or pressurized (at 100 %) .
Stroke limitation
Mech. valve piston movement only within a defined
stroke range.
Limitation of correction speed
Actuator takes a preset time to move from OPEN to
CLOSED or from CLOSED to OPEN.
Correction characteristic for
adaptation to the operating curve
Linearization of the process curve can be carried out.
Insensitivity range
The positioner responds only above a control difference
to be specified.
Direction of action of the controller
setpoint
Reverse of direction of action of the setpoint.
Direction of action of the actuator Reverse of direction of action of the actuator.
Safety position Valve moves to a defined safety position
Code protection Blocking of the keypad or menu
Factory reset Reset to factory settings