About Tuning
Model 493.02 Controller Service
Tuning
211
Tuning without a
specimen
A specimen is required to tune force and strain control modes. Initial
force tuning may be accomplished with the actuator up against the
force sensor. The actuator acts as a specimen reacting against the force
sensor.
1. If you are using a load frame, adjust the load unit crosshead so the
actuator can reach the force sensor.
2. Carefully adjust the actuator using a tuned length control mode so
it contacts the force sensor.
3. You can now switch to force control and proceed with initial
tuning.
Monitoring Waveforms
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.
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.