Conventional dual transducers are often calibrated at ambient and moved to a test piece at a radically different measurement temperature which causes the ‘Zero’, or delay, to change rapidly which can give misleading results. To adjust for this, many UT thickness gauges feature an auto-Zero compensation function for dual element transducers which offer a convenient means of making quick zero compensation calibrations to get started with your thickness measurements and adapt to the dynamic changes in temperature due to calibration and measurement and frequent duty cycling to protect the transducer from damage.

HS582i is compatible with the auto zero features of many gauges including the Olympus 38DL+, Cygnus gauges, GE gauges and Sonotec gauges. For Olympus gauges, we recommend using a cable with probe identification pin to ensure the V-path is also set correctly.

Where the auto-function is not available, an alternative method is to undertake a Zero calibration using a known thickness of the measured material, as you would do if using a flaw detector or meeting the requirements of a standard in your procedure, such as ISO 16809 for ultrasonic thickness measurements. This is often referred to in your gauge user manual as Zero Calibration, or as a method for high accuracy measurements.

Pre-heating your transducer to the measurement temperature and soaking for a minute or two will mean that the calibration is also held for much longer as the temperature remains relatively constant, reducing the need for repeated zero-compensation.

See our user guidance above for more information.