Software On/Off Switching Function; Self-Tuning - gefran 1200 Bedienungsanleitung

Software ON/OFF switching function

How to switch the unit OFF: hold down the "F" and "Raise" keys simultaneously for 5 seconds to deactivate the
unit, which will go to the OFF state while keeping the line supply connected and keeping the process value displayed.
The SV display is OFF.
All outputs (alarms and controls) are OFF (logic level 0, relays de-energized) and all unit functions are disabled
except the switch-on function and digital communication.
How to switch the unit ON: hold down the "F" key for 5 seconds and the unit will switch OFF to ON. If there is a power
failure during the OFF state, the unit will remain in OFF state at the next power-up (ON/OFF state is memorized).
The function is normally enabled, but can be disabled by setting the parameter Prot = Prot +16. This function can be
assigned to a digital input (d.i.G), not é subject to the disabilitazione from parameter "Prot" and excludes deactiva-
tion from the keyboard.

Self-Tuning

The function works for single output systems (heating or cooling) and double action (heating/cooling).
The self-tuning action calculates optimum control parameter values during process startup.
The variable (for example, temperature) must be that assumed at zero power (room temperature).
The controller supplies maximum power until an intermediate value between starting value and setpoint is reached,
after which it zeros power.
PID parameters are calculated by measuring overshoot and the time needed to reach peak. When calculations are
finished, the system disables automatically and the control proceeds until the setpoint is reached.
How to activate self-tuning:
A. Activation at power-on
1. Set the setpoint to the required value
2. Enable selftuning by setting the Stu parameter to 2 (CFG menu)
3. Turn off the instrument
4. Make sure the temperature is near room temperature
5. Turn on the instrument again
B. Activation from keyboard
1. Make sure that key M/A is enabled for Start/Stop selftuning
(code but = 6 Hrd menu)
2. Bring the temperature near room temperature
3. Set the setpoint to the required value
4. Press key M/A to activate selftuning (Attention: selftuning interrupts if the key is pressed again)
The procedure runs automatically until finished, when the new PID parameters are stored: proportional band, inte-
gral and derivative times calculated for the active action (heating or cooling). In case of double action (heating or
cooling), parameters for the opposite action are calculated by maintaining the initial ratio between parameters (ex.:
CPb = HPb * K; where K = CPb / HPb when self-tuning starts). When finished, the Stu code is automatically can-
celled.
Notes:
-The procedure does not start if the temperature is higher than the setpoint (heating control mode) or if the tem-
perature is lower than the setpoint (cooling control mode).
In this case , the Stu code is not cancelled.
-It is advisable to eneable one of the configurable LEDs to signal selftuning status.By setting one of parameters
LED1, LED2, LED3=4 or 20 on the Hrd menu, the respective LED will be on or flashing when selftuning is active.
Notes.: Action not considered in the type of control ON/OFF
Process
Variable
S.P.
Peak
S.P. + t.a.
2
t.a.
73
T
Time