Parametering
Original instructions
Parametering actuating pulse
During autotuning, the output TRI is turned up two actuating pulses. An actuating impulse is identified by two parameters: its time duration (tmax) and its amplitude (step_ampl).
The following value ranges are valid for these parameters: tmax greater than 4 seconds and step_ampl greater than 1 % of the output scale (out_inf, out_sup). The function also monitors even if the TRI output exceeds the threshold for the output scale.
The check occurs when autotune is started.
The following table contains parameter values for some of the typical control methods:
Diagram
tmax(s)
step_ampl (%)
Vol. flow or pressure from liquids
5-30
10-20
Gas pressure
60-300
10-20
Level
120-600
20
Steam temperature or pressure
600-3600
30-50
Module
600-3600
30-50
Performance index: perf
The controller can be modulated for each value in the performance index.
The ERROR: - An internal tag " " was added during translation.perf parameter varies between 0 and 1, which enables the perfparameter to stabilize close to 0 or perf to be set close to 1 to achieve a more dynamic setting (and therefore optimize the response time of disturbance variables).
The perf. performance index varies between 0 and 1, which enables the perf. parameter to stabilize close to 0 or to achieve a more dynamic control (and therefore optimize the reaction time of disturbance variables), if the perf. is set close to 1.
Starting the autotune: START
If this bit is set to 1, the function is activated. At the end of the setting process, this bit must be manually set to 0. If it has just been set automatically, setting the bit to 0 allows the function to be stopped. The PARA_C then retain the last active value. In the example below, the START bit is automatically reset by the program at the end of the setting process.
Example for starting the autotuning
Reverting to the previous setting: PREV
A modification of this bit value enables the exchange of current and previous parameters assuming that no controlling has occurred up to the given time (two consecutive modifications of this bit give the original configuration).
The following Info_AUTOTUNE structural parameters are valid for PIDFF type controllers:
Element of the data structure
Description
p1_prev
KP
p2_prev
TI
p3_prev
TD
The following Info_AUTOTUNE structural parameters are valid for PI_B type controllers:
Element of the data structure
Description
p1_prev
KP
p2_prev
TI
Diagnosis during autotuning: diag
The diagnosis data for the autotune is saved in a double word. The value of this word is retained until autotune is restarted. Additional details on this double word can be found in the Diagnosis section.