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transmitting speed in these two materials, which will cause error. In
addition, different thickness in oxidation layer will cause different error.
Please be careful in this. One can make a reference piece from a batch of
objects by measuring with micron micrometer or caliper, and use it to
calibrate the instrument.
6.7 Abnormal Readout of Thickness
The operator should be able to identify abnormal readout. Generally, the
rust, corrosion, pit and internal defect of the object will cause abnormal
readout. For the solution for that, please refer to chapter 4 and 5.
6.8 Utilization and Selection of Coupling Agent
The coupling agent is for transmitting high-frequency energy between the
probe and the object. If the type of agent is wrong, or the utilization is
wrong, it will cause error or flashing coupling indicator, and it will be
impossible to measure. The coupling agent should be used in proper
amount and be coated evenly.
It is very important to select proper coupling agent. When it is used on a
smooth surface, you’d bet
ter use an agent with low viscosity (such as
coupling agent provided along with the instrument and light engine oil,
etc.). When it is used on a coarse object surface, or vertical surface and
top surface, one can use agent with high viscosity (such as glycerin grease,
consistent grease and lubricating grease, etc.).
Various coupling agents with different components are available
everywhere.
7. Attention
7.1
Cleaning the Test Piece
Since the test pieces supplied along with the instrument will be coated
with coupling agent when being used for inspection, so please prevent it
from rust. After the measurement, the test pieces should be cleaned.
When the weather is hot, never stick any sweat on the pieces. If the
pieces are not to be used for a long time, please paint them with some oil
