Appendix E - Test Track
E-3
11. Close the program and save the Test Track data where you can find it easily.
Checking Calibration
The Dipstick
®
2272 is calibrated at the factory. The calibration constant is very stable, so during a normal
lifetime of Dipstick
®
use, it normally never needs recalibration. Occasionally, we run across a Dipstick
®
that
we built in 1986. When we check one of them, it almost always is still calibrated correctly.
Please note that you cannot calibrate the Dipstick
. The Dipstick
®
2272 is calibrated by our technicians on a
special table under controlled conditions. We guarantee that the calibration of the Dipstick
®
is so good that it
has an expected error of less than 0.001". We are almost always able to achieve an expected error of less than
0.0005". You can check the performance of the Dipstick
on your test track, but you cannot recalibrate the
Dipstick
.
Using the Built-In Test Track Software feature:
Any time you want to check the Dipstick, collect a run on the test track and compare the data to the data you
collected above. If you do it right, and if the floor has not changed because of temperature or humidity or
curling, the IRI will be the same, and the profiles will be the same.
The Dipstick now has a software feature that makes it easy to process the data from a Test Track. Just collect
the out-and-back Run as described above, then use EDIT/TEST TRACK. This software feature will calculate
and apply the Bias (to this Run only) and will Segment the Run at the Turnaround point, Reverse the second
half of the Run, and apply the correct Start point elevation, so you can see how symmetric the two halves of
the Run are.
The best way to collect Test Track data is to keep a Job called “Test Track” on your Dipstick’s handheld
computer. Any time you want to check the calibration, just open this Job and collect new data so you can
compare it to the old data that you previously collected.
If for whatever reason, you collect Test Track data in a different job, you can always use TOOLS/MERGE in
the RoadFace 6 program to merge the old data with the new data. When you overlay today's two 50-ft runs on
top of the original two 50-ft runs, you should see a single profile instead of 4 separate profiles. They will all
lie on top of each other.
If the profiles all lie on top of one another, and if the IRI is are the same for all the Runs, then you can be sure
that your Dipstick is working properly.
If there are minor variations in parts of the profiles, but the profiles eventually merge into one profile, this
usually indicates that you didn't quite walk exactly the same line out and back.
If the profiles start at different elevations, you should use EDIT/RUN HEADER to set the start point
elevations all the same, usually 0.
This is the best way for you to check your Dipstick
®
.
If you have problems when you check the calibration on your Test Track:
Ensure that the floor is clean.
Be sure the feet are in the proper holes.
Check to see if the zeroing is still correct. (Be sure to warm up for 5 minutes before zeroing)
If you continue to have problems when you check the calibration on your Test Track:
Send your Dipstick
®
to us for repair and/or recalibration.
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