Download NI-Motion User Manual - National Instruments

Chapter 13
Torque Control
Speed Control Based on Analog Value
In a system where a feed roll must run at speeds based on an input voltage,
the algorithm to maintain the speed consists of reading the analog voltage
connected to one of the analog channels on the motion controller, and
updating the speed of the axis based on the value of the voltage read. In this
system, the feedback is a normal position sensor, such as an encoder.
Speed Control Based on Analog Feedback Algorithm
Load move constraints
Set operation mode
Set to velocity mode
Start motion
Loop waiting for move complete
Read analog input
Compute new velocity
based on analog input
Load new velocity
Figure 13-7. Speed Control Based on Analog Feedback Algorithm
The analog input could be connected to a force sensor, which ensures that
the tension of a web being fed is maintained.
NI-Motion User Manual
13-14
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