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4.0 TG400 SETUP AND OPERATING PROCEDURES.
In designing the menus for the TG400, particular attention has been paid to simplifying the process of
locating items, then prompting the operator to do something intuitive in order to change control
settings.
4.2 FACTORY Setup Variables
.
When the TG400 is turned on by pressing the ON/OFF control, the LOGO screen is displayed
automatically. When the gage is operated for the first time, or if FACTORY DEFAULT is selected from
memory, all the control variables "default" to specific values (After that they will display the last
previous setup parameters). For many common thickness gaging applications, it is only necessary to
"fine tune" a few variables. Some applications can be started without any adjustments. The
FACTORY setup variables have values that match or nearly match a variety of the most commonly
used transducers for thickness gaging.
With TG400’s broadband receiver and Spike pulser, it is possible to achieve high resolution,
penetration, and sensitivity by using relatively highly damped, broadband transducers for thickness
gaging. Of course, there will be instances where reduced bandwidth transducers will be preferred, but
a surprising number of applications can be satisfied with broadband transducers.
4.3 Thickness Gaging Procedures
Sample Setup procedures
(A Walk Through using a 3/8" 5.0 MHZ Contact Transducer
Once the effects of variables affecting thickness gaging precision are understood, the operator can
quickly diagnose which variables should be adjusted. A good way of observing these effects, and to
become quickly familiar with TG400’s controls is to perform the following procedure:
1.
Attach a highly damped, broadband transducer such as the OPTIMA CHG053 or NOVA C11 (5
MHZ, 3/8 inch element diameter) to the micro-dot connector on the ML-01 transducer cable
supplied with TG400. Insert the Lemo connector in the receptacle marked with a dot on the top
closure of TG400.
2.
Obtain a steel stepped wedge with several known thickness steps. An excellent choice, and the
one upon which this procedure is based, is the OPTIMA Model TBS114. This wedge, made
from 4340 vacuum-melted steel alloy and nickel plated, has five steps precision machined to
thicknesses of 0.100, 0.200, 0.300, 0.400, 0.500 inch (2.54, 5.08, 7.62, 10.16, 12.70mm).
3.
Couple the transducer to the 0.500 inch step using a drop of glycerin, light machine oil, mineral
oil, or low viscosity gel-type couplant. For this familiarization exercise, it will be convenient to
use a rubber band or a small weighted object that will hold the
transducer in place. This procedure will relieve you from having to
hold the transducer in place for an extended period during
familiarization.
4.
Press the ON/OFF key. During this very brief period, TG400
undergoes a host of internal diagnostic checks. Once these checks
are complete, the LOGO screen automatically appears.
5.
An A-trace will appear, along with the Main Menu items and a
thickness readout, the large numbers in the upper area of the A-
trace. This is the FACTORY setup default full-scale range of 2.00
inches (50mm). Also note the large back echo at the second major
horizontal scale division and the thin horizontal bar at 40% full-scale
(FS) amplitude. Observe that this horizontal line extends from the
