MTS Series 793 - Manual (Page 42)

MTS Series 793 Tuning and Calibration
About Tuning
Introduction 42
Monitoring Waveforms While Tuning
When you tune the servoloop you need to monitor the results of your
adjustments. There are two ways to monitor a waveform during tuning.
• An oscilloscope is preferred.
• The controller scope is adequate if you do not have an oscilloscope.
Note Set up your scope to monitor the area of the waveform that shows
characteristics useful for tuning. You can monitor the sensor feedback or
the error signal of the control mode.
What to monitor
The accuracy of the waveform represents how well it reaches the amplitude of
the command or how repeatable the end levels are. The peaks and valleys of
triangle and sine waveforms should be consistent. Use the area of the square
wave after the ringing settles to monitor the end levels.
If the amplitude of the feedback cannot be achieved without going unstable, and
the end levels are repeatable, simply increase the command to achieve the desired
end levels.
Monitoring the
error signal
The error signal shows similar characteristics as a feedback signal. The error
signal represents the difference between the command and sensor feedback. The
following diagrams show the error signal characteristics for each type of
waveform.
These are the areas
of interest on these
waveforms
You do not need to monitor
the entire waveform.
Instead, zoom in on the
area of interest.