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AUTO TUNE
In order to automatically set the PID parameter in PID level (“Pb” proportional band, “ti:
integral time or reset and “td” derivative time or rate), first adjust the controller’s set point to
a value, which closely approximates your application. Allow te system to warm up and
settle down at that operating temperature before attempting an auto-tune process. Set the
“ ” parameter to “ ” for standard type auto tune at and around the setpoint or
“ ” for auto-tune 10% below the current setpoint. The right-most decimal point (AT) on
the PV display begins flashing. The auto tune procedure will take two cycle oscillations.
After that, the controller performs PID control with the “learned” PID value to verify the
results. Finally the PID values will be entered into the nonvolatile memory and then start
the Fuzzy enhanced PID control. The auto tune process can last from several minutes up
to two hours, depending on the system’s parameter. A time out error will occur if the auto
tune process cannot be completed within two hours, in this case, try to set the PID
parameters manually.
Under normal circumstances if it does not complete within say 10 minutes something is
wrong. To abort an auto tune process, simply set the “ ” parameter to “ ”.
On/Off control
The controller can also be set to ON/OFF, PI, PD and P control mode. Set Pb = 0 for
ON/OFF control mode. Set ti = 0 for PD control mode. Set td = 0 fro PI control mode and ti,
td = 0 fro P control mode. The Hysteresis (dead band) 0f ON/OFF control can be set as
follow:
When the second control output (output 2) is equipped the proportional band of output 2
and dead band are defined as follow:
Parameter Retransmission
As an optional extra you can have a retransmission of either the process value or setpoint
value re-transmission. However you can only have either Output 2 or Re-transmission but
not both.
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