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MODIFY
When selecting any of the NDT Setup #s the MODIFY select allows the user to modify a Factory
setup and save it as a specific “User” setup. This allows the user to start with a probe that may
be similar and then modify it to suit a specific probe or application.
UNITS
Allows selection of the basic unit of measurement for the gage. Select between INCHES or
MILLIMETERS.
SYNC
(IP) INITIAL PULSE SYNC
Causes the gage to synchronize the presentation of the A-trace to the Initial Pulse or Main Bang
echo. The Initial Pulse will initially appear at the left edge of the display.
(IF) INTERFACE SYNC
Causes the gage to synchronize the presentation of the A-trace to the first resolvable echo signal
past the initial pulse which is greater or equal to the Interface Threshold. This could represent the
interface of water to metal if using Immersion or bubbler test method or the interface of a plastic
tip to an entry surface is using a delay line transducer. The Interface Pulse will appear at the left
edge of the display.
One is the MAIN range. This is adjusted in the IP mode. Both the menu selectable range and keypad
range change values. The main range will incorporate the total range of the delay material (water,
plastic tip etc) as well as the thickness of the material under test.
The other is IF range which must fit fully into the MAIN range. Best way to set this up is to put
instrument into IP range and be sure that the flaw or back wall echo will always stay on screen. This
means that the water path to the IF will be seen as well as the IF to destination target/back wall. Be
sure this rule stays in place throughout the water path change probability.
It is OK to select a long MAIN range and a short IP. For instance, I even set 20 inches as a MAIN
range and then used a IF range of 2”. The IF range can never be longer than the MAIN range!!! We
think we rang this all out but.. if a limit we didn’t check gets through the gage would likely lock up.
1
Setup transducer/pulser parameters to optimize test as usual.
2
Be sure to start with IP mode (GATES menu)
3
You can adjust these parameters in RF , FW, HW- or HW+
4
On the GATES menu be sure to set an IP block outside the IP noise/ringdown at test sensitivity.
This should not approach the lower limit of the lowest potential Interface position or the Interface
(IF) could get blocked, i.e., If the IP block is set to 2 inches, the IF can not be below that limit or
the next echo over the threshold will be the IF start.
5
In the MAIN or GATES menu, set an IF threshold level (THRESH). User adjustable. 20% - 75%
depending on noise.
6
Set rectification HW+, HW-, RF or FW as desired.
3.0 TRANSDUCER SELECTION
The TG400 is a capable precision thickness gage. Virtually any broad band or general purpose
transducer (application dependant) used with the TG400, as can equivalent transducers produced by
other manufacturers. NDT Systems, Inc. Manufacturers a line of NOVA Series thickness gage
transducers which utilize our patented AutoProbe recognition technology. When using these probes
press PROBE ID and the instrument will recognize the attached probe and set up for a general
purpose test for that probe. The user can then adjust and save the modified setup.
