Chapter 1
Overview of the PID Control Toolkit
©
National Instruments Corporation
1-3
LabWindows/CVI PID Control Toolkit User Manual
PID Control
Currently, the PID algorithm is the most common control algorithm used in industry. Often,
PID is used to control processes that include heating and cooling systems, fluid level
monitoring, flow control, and pressure control. When using PID control, you must specify a
process variable and a setpoint. The process variable is the system parameter you want to
control, such as temperature, pressure, or flow rate. The setpoint is the desired value for the
parameter you are controlling. A PID controller determines a controller output value, such as
the heater power or valve position. When applied to the system, the controller output value
drives the process variable toward the setpoint value.
You can use the PID Control Toolkit functions with National Instruments hardware to develop
LabWindows/CVI control applications. Use I/O hardware, such as DAQ devices, FieldPoint
I/O modules, or GPIB boards, to connect your PC to the system you want to control. You can
use the LabWindows/CVI I/O functions with the PID Control Toolkit to develop a control
application or modify the examples provided with the toolkit.
Using the PID Control Toolkit functions, you can develop the following control applications
based on PID controllers:
•
Proportional (P), proportional-integral (PI), proportional-derivative (PD), and
proportional-integral-derivative (PID) algorithms
•
Gain-scheduled PID
•
PID autotuning
•
Precise PID
•
Lead-lag compensation
•
Setpoint profile generation
•
Multiloop cascade control
•
Feedforward control
•
Override (minimum/maximum selector) control
•
Ratio/bias control
Refer to the
LabWindows/CVI PID Control Toolkit Help
, which you can access by selecting
Start»All Programs»National Instruments»PID Control Toolkit for CVI»LabWindows
CVI PID Help
,
for more information about the functions.
