MTS Acumen - Manual (Page 75)

Understanding the Control Loop
MTS Acumen test systems use closed-loop control, and understanding it lays a foundation for many of
the topics in this document. Closed-loop control is a basic servomechanism concept of controlling a test,
in which a controlling element controls a controlled element.
Closed-Loop Control Concept
The controlling element is the computer, the digital controller, and the MTS MP application. The controlling
element produces a control signal (Command) that represents the direction and amount of force the actuator
should apply to the specimen. The controlled element comprises the electrodynamic motor, the actuator,
and the specimen itself. The controlled element applies the required forces (command) to the specimen
and the specimen reacts to it. The feedback is the response from one of various sensors that indicates
how the controlled element has responded.
Closed Loop Control Step-by-Step
Refer to the following closed-loop diagram. It illustrates how the system operates when you use the Manual
Command panel in the MP application to apply a compressive force to the specimen. Assume that the
system is in Force Control.
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Key Concepts