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Group9- PID function group
1 PID function description
The
Proportional,
Integral
and
Derivative
control function provides closed –loop control, or
regulation of a system process variable (Flow, Pressure, temperature, etc).This regulation is
obtained by comparing a feed back signal with a reference (target) signal, which results in an error
signal. The PID control algorithm then performs calculations on this error signal, based upon the
PID parameter group9.The result of the PID algorithm is then used as the new frequency reference,
or is added to the existing speed reference. The PID target value can be set by parameter 00-05/006,
for example the frequency command (target) can be set from Operator keypad, AI1 Analogue input
or multi function analog input terminals. Select the PID control feed back signal from external
terminal AI2 for a current signal (0-20ma) or a voltage (0-10vdc), depending on setting of Jumper 3
on control board and setting of parameter 2-06.
See PID block diagram below.
※
Note : PID Function is available for controlling the output flow, external fan flow and temperature.
The PID block diagram is as follows
：
1.
To enable PID control, set 02-06=0, ACI on TM2 is defined as the PID feedback signal.
2.
The set point in the above diagram is the 00-05/00-06 input frequency.
Figure 4-26 PID block diagram
