GE PT878GC Manual De Usuario

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Servicing the PT878GC
9-5
April 2004
Setting up the Thickness Gauge
For greatest accuracy in flow applications, the PT878GC can 
measure pipe wall thickness using an optional thickness gauge 
transducer, instead of relying on the nominal pipe wall thickness. 
In Thickness Gauge mode, the PT878GC does not measure flow, 
but it can determine the thickness of most standard metal and 
plastic pipe materials over a range from 0.05 to 3 in. (1.3 to 76.2 
mm). Figure 9-4 below illustrates use of the optional thickness 
gauge.
Figure 9-4:  PT878GC Thickness Gauge in Operation
The PT878GC offers two basic thickness gauge functions: using 
the gauge to measure thickness after entering the pipe material, 
and calibrating the gauge. For the highest possible accuracy, you 
can also calibrate the velocity of sound in the pipe material.
Using the thickness gauge involves three steps:
1. Entering the material and sound speed (in the Material 
window on page 9-7),
2. Measuring the pipe wall thickness (in the Display window on 
3. If the measurement seems unreasonable, examining the 
acoustic signal to diagnose the problem (in the Graph window 
on page 9-10).