EVCO EC3173 - Manual (Page 3)

3
June '96
"AUTO TUNING" FUNCTION
With the "Auto Tuning" function is possible to calculate, when the process is in act, the optimal value of the parameters Pb, PI and Pd
used during the temperature regulation.
To start "Auto Tuning"
Before starting the function is possible to establish the desired kind of regulation:
P.I.D. (if PI and Pd > 0)
P.I. (if PI > 0 and Pd = 0)
P.D. (if PI = 0 and Pd > 0)
P. (if PI and Pd = 0).
If the P2 parameter (enable Auto Tuning) has value 1 is possible to start the "Auto Tuning" function pushing the key for 4 seconds
at least: the display show the label "tun" alternated to the measured temperature value; the instrument keyboard is locked except the
key
.
The function is divided in two phases:
- in the first phase the instrument reaches an initial set, lower than the setpoint and dependent on the start temperature and the final
setpoint, with the previous value of the P.I.D. parameters
- after the reaching of the intermediate set the instrument gives maximum power to the load and measures the feature of the controlled
system to determinate the P.I.D. parameters (Pb always, PI and Pd only if requested); such parameters are stored to keep the value
after a power-down.
The "Auto Tuning" function automatically finishes before the reaching of the setpoint and if there are valid parameters, the P.I.D. regulation
continues with the new calculated parameters: the "tun" label disappear and the display shows the measured temperature value.
To stop "Auto Tuning":
It is possible to terminate the function as follows:
- automatically if the instrument is able to measure all the data necessary to calculate the parameters
- automatically if the instrument is not able to measure the data (because the start temperature was close to the setpoint and there wasn'
t enough time to calculate valid data, or because during the "Auto Tuning" there were some trouble or noise: the output is disconnected,
the buzzer beeping intermittently and on the display lamps the label "---"; pushing the key
for 4 seconds at least is possible to
continue the regulation with the older parameters or try to switch off the power-supply and then switch it on
- manually pushing the key for 4 seconds at least: also in this case the regulation continues with the older set of parameters.