MTS Landmark TWX - Manual (Page 59)

Sensor Limits
One type of detector is a limit detector for sensor input signals. Each sensor can have a high and a low
limit which you can enable separately. When a sensor exceeds (or trips) its upper or lower limit, the selected
detector action occurs.
Detector Actions
The effect a tripped detector has on the system depends on the action you select. The action may result
in the removal of hydraulic pressure from the station, the program stopping, an entry written to the Message
Log, and various other actions you can select.
Setting Limits Before Specimen Installation
Before installing the specimen, it is best practice to set upper and lower force limit detectors to levels that
protect the specimen from damage and minimize the risk of injury to yourself, and to set the action to
"Interlock." For instance, in the Example Test, before you install the specimen you set the maximum tensile
force to 5,000 N (5 kN) to protect the specimen from excessive gripping force. You also set the maximum
compressive force to -50 N (-0.05 kN) to reduce the risk of injury due to a compressive force while working
in close proximity to the actuator.
Setting Limits Before Testing
After the specimen is installed and you are ready to run the test, it is best practice to adjust the upper and
lower force limit detectors to levels that will not interfere with forces that the test procedure is designed to
apply to the specimen. In general, this means you will extend detector limits values. For instance, in the
Example Test, before you run the test you adjust the maximum tensile force to 15,000 N (15 kN), and the
maximum compressive force to -1,000 N (-1 kN). In this case, if you did not adjust the force detector levels
from the levels set before installing the specimen, the detectors would trip as soon as you start the test.
Using the E-Stop Control
If something unusual occurs that requires immediate action, use the Emergency Stop (E-Stop) control to:
• Stop whatever setup operation or test you have in progress, and
• Remove hydraulic pressure from the station.
While using your system, always keep in mind where the E-Stop control is and what it does. The E-Stop
control is located on the load frame control panel. It is a large red button on a yellow striped background.
The emergency stop switch stays activated until you twist the knob as indicated by the arrows.
Understanding the Load Train
It is important to understand the components in the load train. When installing and removing the specimen
and performing test setup, you interact with elements of the load train.
For load frames with base mounted actuators (as used by the typical system in this manual), the load train
consists of all the components between the actuator’s piston rod (the component that moves up and down)
MTS Landmark Test System Operation | 59
Key Concepts