User manual - ATR121 - 19
7 
Controller functions
7.1 
Modifying main setpoint and alarm 
setpoint values
Setpoint value can be changed by keyboard as follows:
Press Display Do
1
§ ¶
or |
Display shows the 
command setpoint 
and OUT1 flashes. 
Increase or decrease 
the main setpoint 
value. Afer 4s display 
shows the process.
2
Press twice 
|
Display shows the 
alarm setpoint and 
OUT2 flashes. 
Increase or decrease 
the alarm setpoint 
value. After 4s 
display shows the 
process.
8 
Tuning
Tuning procedure allows to calculate PID parameters to 
obtain a optimal regulation. It means a stable control of 
temperature/process on setpoint without fluctuations and 
fast response to deviations from setpoint caused by external 
noises.
Tuning procedure includes calculation and setting of the 
following parameters:
•  Proportional band (system inertia, in °C for temperature).
•  Integral time (system inertia expressed in time).
•  Derivative time (defines the intensity of the controller 
reaction to the variation of the measured value, normally 
¼ of integral time). During Tuning procedure, it is not 
possible to change the setpoint.
8.1 
Auto-tune
Tuning procedure calculates the controller parameters, can be 
manual/automatic according to selection on par. 27 
tun
.