National Instruments NI-Motion User Manual page 20

Chapter 1 Introduction to NI-Motion
Supervisory Control
(ms)
User API
Interface
Supervisory
Control
Event Monitoring Interface
I/O
NI-Motion User Manual
Figure 1-5 illustrates the functional architecture of NI motion controllers.
Trajectory Generation
dt
Commands for
Trajectory Generator
Updates Trajectory
Generator Based on
I/O And User
Response
Figure 1-5. NI Motion Controller Functional Architecture
The following list describes how each component of the 73xx controllers
and the NI SoftMotion Controller functions:
• Supervisory control—Performs all the command sequencing and
coordination required to carry out the specified operation
– System initialization, which includes homing to a zero position
– Event handling, which includes electronic gearing, triggering
outputs based on position, updating profiles based on user defined
events, and so on
– Fault Detection, which includes stopping moves on a limit switch
encounter, safe system reaction to emergency stop or drive faults,
watchdog, and so on
• Trajectory generator provides path planning based on the profile
specified by the user
• Control loop—Performs fast, closed-loop control with simultaneous
position, velocity, and trajectory maintenance on one or more axes
(ms)
Cruise
(with Interpolation)
Time
Set Point
Interpolation
New
Set Point
Updated
1-6
Control Loop (µs)
Output
PID
Sensor
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