84
Commander S100 User Guide
7.3.5 Menu 5 - PID controller
The Commander S100 has a dedicated PI (Proportional-Integral) control loop that is suitable for use in applications requiring basic closed-loop
control of a system or process. The output of the PID Controller,
PID Output Percentage
(P1.19), can be used to control the speed of the motor when
selected as a reference in
Frequency Reference 1 Selecto
r (P2.21) or in another reference selector parameter.
Frequency Reference Configuration
(P2.03) can be set to quickly configure the PID output as the drive reference with the settings shown in Table 7-2. There is also a guided setup in
Marshal with easy access to all relevant parameters.
Table 7-2 Frequency reference configuration (P2.03) PID
Figure 7-14 PID controller overview
The response and accuracy of the process is dependent on the PID gain settings. See the descriptions of
PID Proportional Gain
(P5.07) and
PID
Integral Gain
(P5.08) for setting instructions and more information. In the Commander S100 PID Controller the differential term is fixed to 0.
The rate of change of the
PID Reference
(P5.03) can be limited by the
PID Reference Slew Rate Limit
(P5.06). This may be useful to limit the system
overshoot when the setpoint is changed.
Common PID applications
Pressure control
The system will regulate a constant pressure to a process setpoint, where an analog signal proportional to pressure is fed back to the PID loop. The
speed demand for the drive should vary inversely proportional to the system process error i.e. as the pressure increases the drive’s speed decreases
and vice versa.
Level control
The system will regulate a constant level to a process setpoint, where an analog signal proportional to level is fed back to the PID loop. The speed
demand for the drive should vary proportional to the system process error i.e. as the level increases, the drive’s speed increases and vice versa
(assuming level control is on output side of the application).
Temperature control
The system will regulate a constant temperature to a process setpoint by varying a cooling fan speed. An analog signal proportional to temperature is
fed back to the PID loop. The speed demand for the drive should vary proportional to the system process error i.e. as the temperature increases the
drive’s speed increases and vice versa.
PID logic
Built into the PID Controller are a range of tools to control when the PID becomes active and how the output should be interpreted. Under the default
settings, the PID is always enabled and will be used if
PID Output Percentage
(P1.19) is used as the drive reference. However, setting
PID Enable
Selector
(P5.11) or selecting
PID Hardware Enable
(13) as the function of a digital input will disable the PID unless the PID enable condition is active
or there is an active PID Hardware Enable signal. If both of these settings are configured, then both the enable condition and hardware enable signal
must be active to enable the PID.
PID Status Indicators
(P1.20) can be used to monitor the PID enable state and other logic.
Value
Text
Description
8
PID Voltage Ref.
A voltage input on T2 analog input 1 as the reference, and a current input on T4 analog input 2 as the feed-
back. The PID output is used as the drive frequency reference.
9
PID + Feed Forward
A voltage input on T2 analog input 1 as the Feed Forward, and a current input on T4 analog input 2 as the
feedback, the reference is fixed. The PID output is used as the drive frequency reference.
+
-
+
PID Proportional
Gain P5.07
PID Integral
Gain P5.08
PID Control
Upper Limit
P5.10
PID Control
Lower Limit
P5.09
PID
Error
+
P1.19
PID
Percentage
+100%
PID Negative Limit
Enable P5.18
Off (0) = 0%
On (1) = -100%
P1.21
PID Reference
PID Feedback
PID Feed Forward
Содержание COMMANDER S100
Страница 118: ...0478 0650 02...
