8.1. LABORATORY MEASUREMENTS
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of many laboratory instruments1.
2. Calibrate and test the instrument for accuracy and stability.
3. Perform preliminary measurements in the model or laboratory facility to make certain that the instrument will
function adequately at the desired location and under test
conditions.
4. Study measured records to ascertain that quality measurements are being acquired. Improvements in the instrument
or in data collection parameters may become evident at
this step.
5. Although most instruments are relatively simple to operate, the initial setup and operation should be assigned to
an instrument specialist. This is an opportune time to
train additional instrument operators.
6. Those who routinely operate the instrument and equipment should have sufficient experience to detect errors in
the instrument output.
7. Continual data quality inspections should be part of normal operating procedures. If data must be analyzed to
determine quality, these analyses should take soon after
data are collected (preferably the same day). Waiting too
long to examine acquired data is a risk few experienced
engineers are willing to take!
Further general details on instruments, their various components, and
instrument operation are given in Hydraulic Laboratory Techniques (1980).
Details on specific instruments should be obtained from the manufacturers
technical literature or directly from the instrument design engineer.
8.1.4 Measurement Accuracy and Errors
Precision and Accuracy
Measurement of physical quantities in laboratory experiments or physical
model studies provides information about the physical processes under investigation. Simple, direct methods of measurement are often convenient
and acceptable in some simple experiments; however, many experiments re
quire measurements to be made using more complex instrumentation sys
terns. In either case, the character and reliability of the measurements
'Personal communication. Mr. Gary Howell, Coastal Engineering Research Cen
469
of many laboratory instruments1.
2. Calibrate and test the instrument for accuracy and stability.
3. Perform preliminary measurements in the model or laboratory facility to make certain that the instrument will
function adequately at the desired location and under test
conditions.
4. Study measured records to ascertain that quality measurements are being acquired. Improvements in the instrument
or in data collection parameters may become evident at
this step.
5. Although most instruments are relatively simple to operate, the initial setup and operation should be assigned to
an instrument specialist. This is an opportune time to
train additional instrument operators.
6. Those who routinely operate the instrument and equipment should have sufficient experience to detect errors in
the instrument output.
7. Continual data quality inspections should be part of normal operating procedures. If data must be analyzed to
determine quality, these analyses should take soon after
data are collected (preferably the same day). Waiting too
long to examine acquired data is a risk few experienced
engineers are willing to take!
Further general details on instruments, their various components, and
instrument operation are given in Hydraulic Laboratory Techniques (1980).
Details on specific instruments should be obtained from the manufacturers
technical literature or directly from the instrument design engineer.
8.1.4 Measurement Accuracy and Errors
Precision and Accuracy
Measurement of physical quantities in laboratory experiments or physical
model studies provides information about the physical processes under investigation. Simple, direct methods of measurement are often convenient
and acceptable in some simple experiments; however, many experiments re
quire measurements to be made using more complex instrumentation sys
terns. In either case, the character and reliability of the measurements
'Personal communication. Mr. Gary Howell, Coastal Engineering Research Cen