Positioning The Actuator To Install The Specimen; Optimizing System Response Before Testing; Why Tuning Is Beneficial; Loop Tuning For The Example Test - MTS Systems Landmark 370 Series Operation

Key Concepts

Positioning the Actuator to Install the Specimen

You typically position the actuator every time you install a specimen. On the typical system used as an
example in this manual, you use the Manual Command panel in the Station Manager application to
position the actuator. If your system includes a Model 494.05 Handset, you can also position the
actuator using the handset.

Optimizing System Response Before Testing

Optimizing system response is referred to as tuning.

Why Tuning Is Beneficial

Tuning optimizes system response by adjusting the system so that its servoloop responds accurately to
its command signal. When you tune, you are setting the stability and optimizing the response of the
servocontrol loop. Proper tuning improves the performance of your MTS system in the same way that
performing a tune-up on an automobile improves its performance.

Loop Tuning for the Example Test

In the example test you adjust tuning at two points in the procedure:
Setting Initial Values to Ensure Stability
The first point is before you install the specimen or apply hydraulic pressure to the station. The purpose
is to ensure servoloop stability. In this case you simply set tuning controls to conservative values.
Adjusting Values to Optimize Performance
The second point is after you install the specimen, but before you run the test. The purpose is to
optimize system performance with the specimen in the loop. In this case you apply a cyclic waveform
command and adjust tuning parameters so that the feedback (system response) is as close to the
system command as possible. When this is achieved, the system response is optimized for that
particular specimen. If you want to test a different specimen that has different performance
characteristics, you will have to adjust tuning values for the new specimen.

Understanding and Resolving Error Conditions

Resolving error conditions is a normal part of operating an MTS Landmark System. You typically
identify and resolve several error conditions during setup and testing.
Example
When you launch the Station Manager application and open a configuration, the configuration opens in
an interlocked state by design. To help you identify this error condition, the system lights the Interlock
indicator in the main window, and also writes a "Software Interlock" entry into the Message Log, To
resolve this condition, click the Reset button in the Station Manager main window.
Landmark™ Test System Operation 53