User manual - ATR144- 19
8.3 Manual Tune
Manual procedure allows the user greater flexibility to decide
when to update
PID algorithm parameters. During the manual tuning, the
device generates a step to analyze the system inertia to be
regulated and, according to the collected data, modifies PID
parameters.
After selecting Manu. on par. 33 t u n .1 , the procedure can be
activated in three ways:
• Running Tuning by keyboard:
Press FNC until display 2 shows tunE with display 1 on di s .
and then press SET: display 1 shows En a b. Led T switches
ON and the procedure starts.
• Running Tuning by digital input:
Select tunE on par. 94 d.i.1.F. or on par. 101 d .i .2.F. . At first
activation of digital input (commutation on front panel)
led T led switches on and at second activation switches off.
• Running Tuning by serial input:
Write 1 on word modbus 1210: led T switches ON and the
procedure starts. Write 0 to stop the tuning.
To avoid an overshoot, the treshold where the controller
calculates new PID parameters is determined by this
operation:
Tune threshold = Setpoint - “Set Deviation Tune” (par. 37
s.d.t.1)
Ex.: if the sepoint is 100.0 °C and the Par. 37 s.d.t.1 is 20.0 °C the
threshold to calculate PID parameters is (100.0 - 20.0) = 80.0°C.
For a greater precision on PID parameters calculation it is
suggested to start the manual tuning procedure when the
process is not close to setpoint value.
8.4 Tuning performed once
Set once on parameter 36 t u n .1 , or on parameter 98 tu n .2.
Autotuning procedure is executed only once at next ATR144
restart. If the procedure doesn’t work, it will be be executed
at next restart.
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