MTS TestLine - Manual (Page 44)

Closed Loop Control Step-by-Step
The following closed-loop diagram illustrates how the system operates when you use the Manual Control
panel in the Station Manager application to apply a compressive force to the specimen. Assume that the
system is in Force Control.
Basic Closed-Loop Control in MTS Testline Systems
1. You input a compressive command by adjusting the Manual Command slider control in the Station
Manager application.
2. The Station Manager application (program source) instructs the digital controller to generate a signal
that represents the direction and amount of force the actuator needs to apply to the specimen to
accommodate your command.
3. The digital controller generates this command and sends it to the servovalve. The servovalve spool
opens and allows more high-pressure hydraulic fluid (from the Hydraulic Power Supply) to push on the
actuator.
4. The actuator moves and compresses the specimen.
5. The load cell (force sensor) senses the amount of compression and sends this feedback to the digital
controller, where it is compared with your command.
The system automatically repeats Steps 2 through 5 until the desired command is achieved. The digital
controller continues to generate commands to the servovalve to maintain the commanded force on the
specimen.
44 | MTS TestLine Test System Operation
Key Concepts