Using Software Options
Part # 910-250C
91
9.4.3 Gain Adjustment Options
The ADT software features three separate types of gain adjustment for each DAC/TVG
set up. These gain adjustments allow for better inspection precision, easy manipulation of
curves and live peak information, and transfer correction.
9.4.3.1 Scanning Gain
In order to quickly find and identify potential defects, it is common to increase the gain on
the EPOCH 4PLUS from the Reference (calibration) Gain for scanning purposes.
However, once a potential defect is identified, this gain may be removed to view the
reflector at REF Gain level, set at calibration. The ADT software for the EPOCH 4PLUS
can add temporary scanning gain for inspection purposes. This scanning gain affects only
the live A-Scan and does NOT adjust the level of the DAC curve(s) set up on screen.
To add temporary scanning gain, follow the steps below:
1. Press the GAIN key.
2. Select either a 0.1 dB or 6 dB adjustment increment using the [F1] or [F2] keys,
respectively.
3. Use the up and down SLEWING keys to adjust the scanning gain by the desired
increment. The scanning gain is displayed at the upper left of the screen, next to the
calibrated Reference Gain level.
4. Once the desired scanning gain level is set, use the SCAN DB Key [F4] to toggle
between the base (reference) gain and the adjusted scanning gain.
5. Scanning gain is disabled using the OFF key [F5].
Note: When reference correction is active, the digital comparison between a
captured reflector and the DAC curve will be accurate even with scanning
gain applied to the inspection, provided that the gated echo is not saturated.
9.4.3.2 Curve Adjustment Gain (DAC Gain or TVG Gain)
The overall gain level of the entire DAC curve and TVG line setup can be adjusted higher
or lower from the Reference Gain. Most inspection codes do not allow reflectors to be
sized below 20% of FSH. Therefore, to inspect beyond a certain depth/sound path time
within a part, it is necessary to raise the gain of both the live A-Scan and the DAC curve to
continue inspection. This is accomplished on the EPOCH 4PLUS using the DAC Curve
Adjustment Gain. This gain adjustment is displayed at the top right corner of the live A-
Scan at all times and is adjusted using the following steps:
1. Press the STEP = X.X key [F5] to choose the increment of the gain adjustment
desired.
2. Use the UP and DOWN arrow keys to adjust the Curve Adjustment Gain by the
selected increment either positive or negative.
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