How do I check my MTI-2100 Edge Probe for proper operation in High Resolution Mode?
If an edge probe becomes damaged or the lamp begins to wear out it is very possible you will read lower Total Indicated Runout (TIR) signal in high resolution mode. Here is what has happened: Assume a chipped prism or severely scuffed prism face. The user initiates calibration mode and the MTI-2000 scales the probe up to 10 volts output in Normal (X1 gain). The user then positions the probe at the 50% occlusion over the disk edge and selects High resolution probe sensitivity. Here is where the sensitivity problem occurs. The Probe may only increase X4 or X5 not X7.5 as intended. The reason is that out of a total lamp power of 100% the initial cal cycle used up more than 13% of the total light available so perhaps 20% of the total light available. Now when you select high resolution and the lamp servo commands 7.5 times more powerful light the servo is only able to deliver 100% light not 7.5 x 20% or 150% as was desired by the user and required by the instrument calibration. This means
