Chapter 4 Software Index
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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, AI2 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
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