Selftuning - gefran GFW ADV Configuration Manual

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.
Selftuning
Process
variable
S.P.
Peak
S.P. - t.a.
2
t.a.
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.
31
s. t v
140
diG.
618
diG. 2
3
SELFTUNING
bit
305*
Read state
0
SELFTUNING STATE
bit
68
STATE OF DIGITAL
INPUT 1
bit
92
STATE OF DIGITAL
INPUT 2
bit
296
56
T
Time
Enable selftuning,
R/W
autotuning, softstart
R/W Function digital input
R/W Digital input 2 function
OFF = Selftuning in Stop
R/W
ON = Selftuning in Start
R/W Instrument state (STATUS_W)
OFF = Selftuning in Stop
R
ON = Selftuning in Start
OFF = Digital input 1 off
R
ON = Digital input 1 on
OFF = Digital input 2 off
R
ON = Digital input 2 on
Autotuning and selftuning enable state
R
(FLG_PID)
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.
Selftuning, autotuning, softstart table
Autotuning
continuous
0 NO
1 YES
2 NO
3 YES
4 NO
5 YES
6 Autotuning One-shot
8* WAIT
9 GO
10* WAIT
11 GO
12* WAIT
13 GO
(*) +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.
See: Table of digital input functions
See: Table of instrument settings
See: Table of digital input functions
bit
3 Selftuning on
6 Autotuning on
see: CONTROLS - PID parameters
Selftuning Softstart
NO NO
NO NO
YES NO
YES NO
NO YES
NO YES
NO NO
NO NO
YES NO
YES NO
NO YES
NO YES
80963B_MSW_GFW_11-2012_ENG
0
0
0