Dakota MAX II, Operation Manual

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MAX II Bolt Tension Monitor
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9) Finally, press the MEAS key to return to the measurement screen, set up a
new bolt group, and begin taking readings.
8.6 Calibration / Zero Bars & Triple Sided Glass Block
Historically a set of 3” & 6” mild steel calibration bars, or a triple sided glass block
have been used for performing a probe zero. The bars/block are generally measured
and certified to a specific set of standards in a professional calibration lab, and the
corresponding length, velocity, and temperature coefficient are documented. Dakota
Ultrasonics carries a custom set of cal bars and an optical glass block that are
measured and calibrated according to national standards. The primary advantage of
using these bars/block versus setting a standard bolt aside, as explained in the
previous section, is the possibility of losing the stand alone bolt. Because the factory
3” & 6” bars and glass block are calibrated with documentation, these can be
interchanged between units and cal bars/blocks.
While the 3” & 6” bars provide two specific points to demonstrate linearity, the triple
sided glass block has a third reference point. The glass block has a 1”, 2”, & 3”
reference. Generally the user will set up the two-point calibration on the 1” & 3” sides
first, and use the 2” side for additional verification purposes. This section explains
the procedure for using the factory calibration bars and glass block as a means of
probe zeroing the
MAX II .
The first step is to setup a group to document our probe zero data, as previously
outlined in section 8.3. By doing this, all the values and settings will be saved to the
cell location for easy recall at a later time. This will allow the user to easily verify the
zero value and make any necessary changes to the
MAX II , by adjusting the zero
value or temperature depending on the circumstances or conditions.
Now that the bolt group has been created to document the probe zero data, we’re
ready to get started with the probe zero process. The first thing to note is, the
procedures in the next section demonstrate a
Two-Point calibration. However, the
same procedures apply to the One-Point calibration option also. The user would
simply follow the same procedures and ignore references to the second point.
Measuring Calibration Standards – For the First Time