User manual

Introduction 7

1.6 Internal Probe

The VisualDepth internal probe contains a spring loaded gauge wire coupled to a linear

encoder, a video camera, a light source, and a probe positioning system. The VisualDepth

main module measures travel of the gauge wire when it is pressed against a reference

surface and compares it to travel when the gauge wire is inserted into a pit. The difference

between two readings is displayed in VisualPlus software as pit depth. Two reference

prongs are used to make sure that the gauge wire travel is measured from a known location.

The probe should be pushed against the cylinder surface until both prongs make contact

with the surface.

The probe cable should be connected to the VisualDepth main module Internal Probe port

on the front panel.

The probe positioning system is operated via a handwheel mounted in the probe handle.

Once the internal probe has been inserted into the cylinder, loosen the thumbscrew and

rotate the handwheel into an appropriate position. Tighten the thumbscrew to lock the

handwheel and probe in place for measurement. When inspecting sloped portion of the tank