National Instruments NI-Motion - Manual (Page 20)

Chapter 1 Introduction to NI-Motion
NI-Motion User Manual 1-6 ni.com
Figure 1-5 illustrates the functional architecture of NI motion controllers.
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
Trajectory Generation
(ms)
V
elocity
Time
dt
New
Set Point
Updated
Updates Trajectory
Generator Based on
I/O And User
Response
Cruise
Decel
Accel
Jer
k Jer
k
Control Loop (µs)
(with Interpolation)
F
eedbac
k
Interpolation PID
Sensor
Output
Supervisory Control
(ms)
User API
Interface
I/O
Supervisory
Control
Commands for
Trajectory Generator
Event Monitoring Interface
Set Point