Burkert Type 8693 - Manual (Page 146)

146
Start-up and operation of the
position controller Type 8693
23.6.6. P.TUNE - Self-optimization of the process controller (process
tune)
The control system of the Type 8693 has an integrated PID process controller. When an appropriate sensor is
connected, any process variable such as flow rate, temperature, pressure, etc. can be controlled.
To obtain a good control performance, the structure and parameterization of the controller must be adjusted to
the properties of the process (controlled system).
This task requires experience in control technology as well as in measurement aids and is time-consuming.
Therefore, the control system of type 8793 features the
P.TUNE self-optimization function which determines the
structure and parameters of the process controller at the press of a button.
The determined PID parameters can be seen via the operating menu (
P.CONTROL - PARAMETER) and modified
at will.
Operating mode
When the P.TUNE function runs, the process is automatically identified. To do this, the process is initiated with a
defined disturbance variable. Characteristic process parameters are derived from the response signal and are the
basis for determining the structure and parameters of the process controller.
If the P.TUNE self-optimization is used, optimum results are obtained based on the following requirements:
• Stable or stationary conditions with reference to the process actual value PV when P.TUNE starts.
• Implementation of the P.TUNE in the operating point or in the operating range of the process control.
Operation
The P.TUNE function can be run when the process controller is either in automatic or manual mode.
When P.TUNE ends, the control system is in the operating mode which was set previously.
The procedures described in the following sections a) and b) are not mandatory requirements for running
the
P.TUNE function. However, they increase the quality of the result.
a).P.TUNE.in.manual.mode
The.operator.is.on.the.process.operating.level.
→
Press the arrow keys to display the process value PV.
→
Switch the control system to manual mode by pressing the right key HAND.
The requirements mentioned in the previous chapter to obtain optimum results are set in the following Way:
→
Manually open or close the control valve by pressing the OPEN / CLOSE arrow keys and move the process
value up to the required operating point or operating range.
→
As soon as the obtained setting is temporally constant, start the P.TUNE function (see chapter “Start the
P.TUNE function”).
english
Type 8692, 8693