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© Retrotec 2017
8.
What to do if you have trouble with the gauge
Knowing the common causes of erroneous readings will increase your confidence in the results. It is often
assumed the gauge must be regularly calibrated in order to get accurate readings, but this thought
obscures the fact that most gauge problems do not result from incorrect calibrations. The following list
provides approximate percent probabilities based on our experience for certain types of gauge problems.
Notice that gauge calibration is one of the smallest, and even that can usually be eliminated by following
the gauge check procedures in section 7 this manual.
Table 6: Causes of common problems with gauges
Problem caused by
Error frequency
Error range
Comments
Tubing is crimped shut
5%
25 to 90%
Usually noticeable because gauge does not move, but the
blockage may be partial, which could cause an erroneous
result.
Water in tubing
10%
75-90%
Possible only in wet areas. If gauges sent in to be
repaired or calibrated, the water evaporates and the user
never discovers the cause.
Improper Device selected
2%
20 to 90%
Not common because the wrong Range Configuration
choices will likely be noticed on the gauge.
Improper Range Configuration
selected
5 to 25%
50%
Very common unless gauges checked before and after
each measurement to ensure the right Range is in use.
Improper use of reference tube for
pressurization
5%
25%
Pressurization is seldom used, but if the technician is
improperly trained, they may not set the equipment up
properly for this test.
Time averaging set too high or too
low
25%
5 to 10%
If the gauge is fluctuating too much it will be difficult to
read. If the time averaging is too high, the pressure may
have changed but that change is not reflected in the
reading.
Wind
25%
10%
These errors can be eliminated by long-term averaging or
by multiple pressure pickups.
Out of calibration
5%
1-50%
Gauges can go out of calibration in a week or may take 10
years. It is impossible to tell unless the readings seem
unreasonable.
Out of calibration with regular
checks
0.5%
1-2%
Regular gauge checks can eliminate most of the
calibration problems, by identifying large errors
immediately, and before erroneous test results can be
taken. It is unlikely that errors in excess of 2% would
occur if the gauges checked before each use.
Proper training can eliminate almost all of the above errors.
8.1
Re-calibrate touchs
creen if keys don’t respond well
to taps
If the soft keys on the touch screen seem not to be responding to the user touch, the screen calibration
may need to be adjusted. The
key allows the user to enter new corner points
for the touch screen to re-calibrate the screen. The calibration process can ensure the correct functions
are being activated when a user touches the screen in the area of the keys. Each display varies slightly so
the touch screen is calibrated at the factory before being sent out to the user, but can change over time.
If you end up not being able to get the gauge to respond to your taps at all (for instance if you tap in the
wrong location during the [Re-calibrate touchscreen] routine and confuse the gauge), you will have to
connect the DM32 to a computer and run the
DM32 Configurator
software
–
the “Settngs” tab has a button
you can click which will cause the connected DM32 to run the [Re-calibrate touchscreen] procedure.
