YASKAWA A1000 HHP Programming Manual page 34

1.2 b: Application
n D Control
D control predicts the deviation signal by multiplying its derivative (slope of the deviation) with a time constant, then adds
this value to the PID input. This way the D portion of a PID controller provides a braking action to the controller response and
can reduce the tendency to oscillate and overshoot.
D control tends to amplify noise on the deviation signal, which can result in control instability. Only use D control when
absolutely necessary.
n PID Operation
To better demonstrate PID functionality,
level.
n Using PID Control
Applications for PID control are listed in
Application
Machinery speed is fed back and adjusted to meet the target value. Synchronous control is
Speed Control
performed using speed data from other machinery as the target value
Pressure Maintains constant pressure using pressure feedback.
Fluid Control Keeps flow at a constant level by feeding back flow data.
Temperature
Maintains a constant temperature by controlling a fan with a thermostat.
Control
n PID Setpoint Input Methods
The PID setpoint input can be input from one of the sources listed in
If none of the sources listed in
listed in Table 1.19 becomes the PID setpoint.
PID Setpoint Source
Analog Input A1
Analog Input A2
Analog Input A3
MEMOBUS/Modbus Register 0006 H
Pulse Input RP
Parameter b5-19
Note: A duplicate allocation of the PID setpoint input will cause an oPE07 (Multi-Function Analog Input Selection Error) alarm.
n PID Feedback Input Methods
Input one feedback signal for normal PID control or input two feedback signals can for controlling a differential process value.
34
Figure 1.20 illustrates the PID output when the PID input (deviation) is at a constant
PID input
PID Output
Figure 1.20 PID Operation
Table 1.18.
Table 1.18 Using PID Control
Description
Table 1.19 are used, the frequency reference source in b1-01 (or b1-15) or one of the inputs
Table 1.19 PID Setpoint Sources
Set H3-02 = C
Set H3-10 = C
Set H3-06 = C
Set bit 1 in register 000F H to 1 and input the setpoint to register 0006 H
Set H6-01 = 2
Set parameter b5-18 = 1 and input the PID setpoint to b5-19
YASKAWA ELECTRIC SIEP YEAHHP 01B YASKAWA AC Drive – A1000 HHP Programming Manual
Time
PID output
I control
D control
P control
Time
Table 1.19.
Settings
Sensors Used
Tachometer
Pressure sensor
Flow rate sensor
Thermocoupler,
Thermistor