Desin Instruments HS-7000 Series, General Instructions Manual

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CONTROLLER POSITIONER MODE
The Positioner Control is a type of control where the controller produce the «servoposition»
function which is normally provided in the servovalves, thus, allowing to use of low cost
motovalves with feedback potentiometer.
The Positioner, manages the process control valve by means of its two outputs Open or Close,
until the position in % corresponding to the manipulated variable (MV) of the PID, comparing
it to the signal of the feedback potentiometer that idicates the real position of the valve.
If the process variable goes below the setpoint SP, the Positioner control gives the order to
Open, if the process variable goes over the setpoint SP, the Positioner control gives the order
to Close, until it is balanced with the value given by feedback potentiometer.
This type of control is equivalent to a continuous control type, but instead of using a servovalve
controlled by a 4-20mA signal, a motovalve with feedback potentiometer is used.
The HS-7000 controllers, can be programmed for one single loop operating as Positioner
control type, being always required the feedback of the position of the motovalve, by means
of a potentiometer associated to the motor of the valve, which transmits its position to the
instrument through the analog input available. This signal is compared internally to the PID
correction signal, to Open or Close, to put the valve in the position according to the PID control
signal.
HOW TO SET THE PARAMETERS OF A CONTROLLER POSITIONER
The parameterization of this type of control is equal to the continuous control of 4-20mA output.
The PID parameters setting can be done in Manual or Automatic mode, following the same
procedures explained for a conventional control, including the Fuzzy-Logic function.
Important:
- Once the wiring connection is realized, check that the Open-Close sequence is correct.
- Check that the LEDs on the front panel are associated to the Open-Close actions.
PREPARING THE DEVICE TO OPERATE AS CONTROLLER POSITIONER
This type of configuration should be done using the LoopWin software.
HS-7000 for Positioner Control Loop with one
Feedback Potentiometer signal.