7-11
● PA17 (PID computation initialize manipulated variable)
Under the conditions listed below, a PID computation starts using the value set in
PA17.
• When there is a mode change from READY AUTO to RUN AUTO.
• When the controller is powered up in RUN (or HOLD, FAST, END) AUTO
mode.
• When auto-tuning ends.
Since the PV, SP and PID parameters affect a PID computation, the first
manipulated variable of a PID computation may not be the same as the value set in
PA17.
● PA31 to PA38 (event on delay groups 1 to 4, event/delay time)
• On delay can be performed on up to 4 events.
• PA31, PA33, PA35 and PA37 determine which events are to be processed.
• In a code event involving several event outputs, event on delay has to be set
separately for each output.
• All processes including event output standby on/off are processed before on
delay processing. When the event output ON condition remains on for longer
than the on delay time, the event output stays on.
• This is shown in the diagram below.
● PA41 (EG1 LED display event number)
The console EG1 LED lights when an event number set in PA41 goes on and is off
when it goes off. Note, however, that the EG1 LED is off when PA41 is set to 0.
● PA42 (EG2 LED display event number)
The console EG2 LED lights when an event number set in PA42 goes on and is off
when it goes off. Note, however, that the EG2 LED is off when PA42 is set to 0.
● PA43 (PID computation initialize)
When SP changes abruptly due to ADV, the derivative action of a PID
computation, may cause an excessive change in the manipulated variable of the
computation.
For this reason, the initialization of a PID computation is performed to suppress an
excessive change.
But the initialization of a PID computation means that PID computation continuity
is lost which may affect operating conditions. A PA43 setting allows the user to
turn on or off initialization and determine its conditions.
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