Co- Tune: Start-Up Adaptation - Samson TROVIS 6493 Mounting And Operating Instructions

7.3.3

-CO- TUNE: Start-up adaptation

The purpose of the adaptation is to quickly determine the best settings for the control param-
eters KP, TN and TV with minimum knowledge of the process to be controlled.
The control parameters are calculated by the controller from the step response according to
the rules introduced by Chien, Hrones and Reswick for the aperiodic control operation and a
good reference action.
Observe the following:
− The adaptation can only be used for controlled systems with self-regulation.
− The controlled variable must be as constant as possible at the beginning of the adapta-
tion.
− The disturbance variables must not be changed during the adaptation.
First set the manipulated variable Y to a start value. In a start-up adaptation with 'run ADP.S'
setting, the analog output is stepped up or down by the step change value of the manipulat-
ed variable (Y.JMP parameter). The controller waits for the response from the controlled sys-
tem until a new stable state of the controlled variable is reached. The controller determines
the control parameters from the course of the controlled variable. After the adaptation is
completed, the controller issues the output value again which was active in manual mode be-
fore the adaptation.
Before the adaptation, the operating point of the manipulated variable must be known. If it is
not known, it can be determined in the manual mode. To proceed, set the manipulated vari-
able Y in manual mode so that the controlled variable X has the same value as the set point
W. This output value is the operating point.
The step change of the manipulated variable must be large as possible and be located
around the operating point (e.g. start value below the operating point and end value above
it). On determining the step change value Y.JMP and the start value, make sure that the out-
put value is within the range of the manipulated variable and that the controlled variable is
within the measuring range. Furthermore, make sure the controlled variable for the process
does not assume any impermissible values. Check this point before the adaptation: in manu-
al mode set the output value after the step change and then the output value before the step
change.
To run start-up adaptation, proceed as follows:
The compact controller is in the operating level.
EB 6493 EN
Start-up and configuration at the device
7-23