Setting The Zero Point (Probe-Zero) - Elcometer 205 Operating Instructions Manual

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Note: Occasionally, a small film of couplant will be drawn out between the transducer and the surface as
the transducer is removed. When this happens, the gauge may perform a measurement through this
couplant film, resulting in a measurement that is larger or smaller than it should be. This phenomenon is
obvious when one thickness value is observed while the transducer is in place, and another value is
observed after the transducer is removed. If this happens, take the reading again using less couplant.

5 SETTING THE ZERO POINT (PROBE-ZERO)

Setting the zero point of the gauge is important for the same reason that setting the zero on a mechanical
micrometer is important. If the zero point of the gauge is not set correctly, all of the measurements the gauge
makes will be in error by some fixed number. When the zero point of the gauge is set, this fixed error value
is measured and automatically corrected for in all subsequent measurements.
To set the zero point:
1. Plug the transducer into the gauge ensuring that the connectors are fully engaged. Check that the
wearface of the transducer is clean and free of any debris.
2. Switch on the gauge.
3. The battery compartment cover on the top end of the gauge acts as a metal 'probe-disc'. Apply a
single droplet of ultrasonic couplant to the top of this disc.
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