MTS 709 Alignment System - Manual (Page 21)

709 Alignment System Alignment Procedure Overview 21
Alignment Procedure Overview
Following is an overview of a typical alignment procedure. It is intended as a
guide and will apply to most system configurations.
1. Check the controller setup and tuning before inserting the alignment
specimen instrumented with strain gauges: With no specimen clamped in the
grips, verify the stroke control tracks without drift. With an expendable
specimen clamped in the grips, verify the load control smoothly tracks a
slow (less than 1 Hz) function generator ramp.
2. Insure that the specimen is properly connected to the 709 electronics. Wait
20 to 30 minutes to insure there are no temperature gradients.
3. Confirm the specimen geometry and end levels in the specimen tab. The end
levels are typically set to the Load @ 2000 µe shown in the second column.
4. In the align tab, check the specimen offsets. Do this by toggling between
None, Current Tare, and Specimen Gauge. Current Tare and Specimen
Gauge (stored and averaged offsets) should be very close (within 5%). If
they are not, the Specimen Gauge offsets should be cleared and re-
established.
5. With the system in displacement control install the specimen in the lower
grip (or upper grip if desired). Clamp that end of the specimen in the grip.
6. Zero the load cell.
7. Move the actuator until the other end of the specimen is in the proper
location of the other grip is in position to clamp.
8. Now check to see if the Bent Offset is properly established. Do this by
toggling between Current Tare and Bent Offset. Normally, you should see
very little change between Current Tare and Bent Offset. Note that Bent
Offset is not really needed unless the specimen is not straight (i.e. has
manufacturing eccentricities or has been deformed).