Pulser Adjustments; Pulse Repetition Frequency (Prf) - Olympus EPOCH 650 User Manual

• +6 dB
Used to add 6 dB to the reference gain. You add 6 dB each time you press this
button.
• –6 dB
Used to subtract 6 dB from the reference gain. You subtract 6 dB each time you
press this button.
5.4

Pulser Adjustments

The pulser settings in the EPOCH 650 ultrasonic flaw detector are accessible from the
Pulser menu item. The pulser setup parameters are:
•

Pulse Repetition Frequency (PRF)

• Pulse Energy (Voltage)
• Damping
• Test Mode
• Pulser Type
• Pulser Frequency Selection (Pulse Width)
5.4.1 Pulse Repetition Frequency (PRF)
Pulse repetition frequency (PRF) is a measure of how often the transducer is being
pulsed by the electronic circuitry in the EPOCH 650 ultrasonic flaw detector.
PRF is typically adjusted based on the test method or test piece geometry. For parts
with long sound paths, it is necessary to lower the PRF to avoid wrap-around
interference that results in spurious signals on the display. For applications with rapid
scanning, it is often necessary to use a high PRF rate to assure that small defects are
detected as the probe moves along the part.
The EPOCH 650 allows you to manually adjust the PRF from 10 Hz to 2000 Hz in
50 Hz (coarse) or 10 Hz (fine) increments. The instrument also has two Auto-PRF
settings to automatically adjust the PRF based on screen range.
To select a PRF adjustment method
 Select Pulser > PRF Mode, and then vary the setting. The available choices are:
DMTA-10055-01EN, Rev. A, February 2015
Adjusting the Pulser/Receiver 107