Bently Nevada Proximity Probe Calibration Simulator
Bently Nevada Proximity Probe Calibration with the TK-3 Test Kit
A proximity probe makes an eddy-current field at its tip. The closer the steel shaft, the stronger the eddy currents, and the Proximitor turns that into a negative voltage. The TK-3 micrometer moves a steel target to exact gaps so you can check the scale factor (200 mV/mil for a 3300 XL 8 mm system) and the linear range. Wind the micrometer, record 9 points, and see if the probe passes. Make deliberate mistakes in step 1 to see what each does.
Procedure map (click a step)
Hint
1 Pre-checks and bench setup
Mistake lab (try them, then fix them)
TK-3 micrometer
| Dial reading | |
| Proximitor output (meter) | |
| Nominal at 200 mV/mil | |
| Eddy-current coupling |
Results table
| Gap | Output | Incr. SF | DSL |
|---|
Graph 1: Output voltage versus gap
x: gap (mil), y: output (negative volts, shown as positive). Green dots = your recorded points, green line = best-fit straight line, green band = allowed error, orange dashed = ideal 200 mV/mil, red dot = now. A good probe: dots sit on the line inside the shaded linear range.
Graph 2: Deviation from the straight line (DSL)
Each bar is the error at that gap in mil. Green band = allowed. Bars outside it are red.
Graph 3: Scale factor in each 10 mil step
Slope between neighbouring points in mV/mil. Green band = 190 to 210, dashed = 200. Dips show a bent or noisy probe.
Calibration certificate
| Scale factor (best-fit slope) | |
| Worst deviation from straight line (DSL) | |
| Output at 50 mil (nominal -10 V) | |
| Result |
Mistake and what you see
| Mistake | What you see |
|---|---|
| Probe + extension length does not match the Proximitor (5 m / 9 m) | Scale factor wrong, linear range shifted |
| Target is not 4140 steel | Scale factor low (aluminium is far lower) |
| Supply below -24 V | Top end flattens, linear range shrinks |
| Loose or dirty connector | Noisy, jumping voltage |
| Damaged probe tip | Wavy line, poor linearity |
| Zero not set at touch, or reversing the micrometer | Every gap is off by a constant (backlash) |
| Forcing the target onto the tip | Crushed tip: replace the probe |
