Calibration; Basic Setup - Olympus EPOCH 650 User Manual

9. Calibration

Calibrating the EPOCH 650 ultrasonic flaw detector is the process of adjusting the
unit so that it measures accurately on a particular material, using a particular
transducer at a particular temperature.
In calibrating the instrument, you set the zero offset and velocity parameters. The zero
offset (sometimes referred to as probe delay) is set to compensate for the dead time
between the firing of the main pulse and the entry of the sound into the test piece. The
velocity is set so that it matches the material velocity of the test piece.
The EPOCH 650 features advanced auto-calibration that provides for a fast and easy
calibration process. This section details the procedures to calibrate the EPOCH 650
using the four basic transducer configurations: straight beam, delay line, dual
element, and angle beam.
9.1

Basic Setup

Until you are completely comfortable operating the EPOCH 650 ultrasonic flaw
detector, we recommend using a basic setup procedure before starting the actual
calibration.
To setup the EPOCH 650 before calibrating
1. Press dB to select an initial gain value that is appropriate for the calibration.
If the appropriate gain level is unknown, set the initial gain at 20 dB and adjust it
as necessary during calibration.
2. Choose Basic > Velocity, (group 1/5) and then enter an approximate velocity for
the test material. See "Sound Velocities" on page 307 for a table with sound
velocities for various materials.
DMTA-10055-01EN, Rev. A, February 2015
Calibration 143