On the Extensometer final inspection sheet, what does the (+Output) at Overtravel Stop and (-Output) at Overtravel Stop mean (Figure 1)?
Figure 1 – Extensometer Final Inspection Sheet
The output at the overtravel stop is the sensor signal output when the extensometer has gone through the whole range of motion and hit the hard stops to limit travel. The over travel stops are meant to prevent the test from damaging the extensometer.
The intent is to tell the user that if you see that output from the sensor, you have used up the useful range of the sensor.