53
80415F_MSW_GFX4-IR_05-2019_ENG
The procedure runs automatically until termination. At termination, the new PID parameters are saved: proportional band,
integral and derivative times calculated for the current action (heat or cool). In case of double action (heat + cool), the parameters
for the opposite action are calculated by maintaining the initial ratio between the parameters (example: Cpb = Hpb * K; where K =
Cpb / Hpb when selftuning is started). At termination, the Stu code is automatically cancelled.
Note:
The procedure does not start if temperature exceeds the setpoint for heat control, or is below the setpoint for cool control.
In this case, the Stu code is not cancelled. It is advisable to enable the LEDs to signal selftuning state. By setting parameter Ld.St
= 4 on the Hrd menu, the appropriate LED will light up or flash when selftuning is active.
140
diG.
R/W
Function digital input
0
See: Table of digital input functions
618
diG.2
R/W
Digital input 2 function
0
3
bit
SELFTUNING
OFF = Selftuning in Stop
ON = Selftuning in Start
R/W
SELFTUNING
This function is valid for single-action (either heat or cool) systems and for double-action (heat/cool) systems.
Selftuning is activated to calculate the best control parameters when starting the process. The variable (example:
temperature) must be the one assumed at zero power (room temperature).
The controller supplies the maximum power set until reaching an intermediate point between starting value and the setpoint,
then resets power. The
PID
parameters are calculated by evaluating superelongation and the time needed to reach the peak
(
N.B.: This action is not considered in ON/OFF control
).
When the function is completed, it disengages automatically, and the control proceeds to reach the setpoint.
Peak
T
S.P.
t.a.
Time
Process
variable
S.P. - t.a.
2
Selftuning
How to activate selftuning:
A. Activation at switch-on
1. Set the setpoint to the desired value.
2. Enable selftuning by setting parameter Stu to 2
3. Switch off the instrument.
4. Make sure that temperature is near room temperature.
5. Switch on the instrument.
B. Activation via serial command
1. Make sure that temperature is near room temperature.
2. Set the setpoint to the desired value.
3. Run the Start Selftuning command.
see: CONTROLS - PID parameters
305
R/W
Instrument state (STATUS_W)
0
See: Table of instrument settings
31
s.tv
R/W
Enable selftuning,
autotuning, softstart
0
Autotuning
Selftuning
Softstart
continuous
0
NO
NO
NO
1
YES
NO
NO
2
NO
YES
NO
3
YES
YES
NO
4
NO
NO
YES
5
YES
NO
YES
Autotuning One-shot
8*
WAIT
NO
NO
9
GO
NO
NO
10*
WAIT
YES
NO
11
GO
YES
NO
12*
WAIT
NO
YES
13
GO
NO
YES
Selftuning, autotuning, softstart table
(*) +16 with automatic switching in GO if PV-SP > 0.5% f.s.
+32 with automatic switching in GO if PV-SP > 1% f.s.
+64 with automatic switching in GO if PV-SP > 2% f.s.
+128 with automatic switching in GO if PV-SP > 4% f.s.
