Myron L 6P (includes Addendum 10-01) User Manual
Page 13
4.
Press ; the display will change to the other unit.
5.
Press
; all temperature readings are now in degrees last
shown.
N O T E : Tempco will still be shown in %/°C.
IX.
TOTAL RETURN to FACTORY SETTINGS “FAC SEL”
There may come a time when it would be desirable to quickly reset all the
recorded calibration values in the instrument back to the factory settings.
This might be to ensure all calibrations are set to a known value, or to give
the instrument to someone else free of adjustments or recorded data for
a particular application.
1.
Press .
2.
Press to display the stored memory records.
3.
Press repeatedly until
you pass the CL
r
ALL and the
C-F locations. The display will
show a “
FAC SEL
”
(see Figure 13).
4.
Press to accept the resetting.
22
CAL
MCLR
COND
CAL
MCLR
COND
MR
MR
Figure 13
Figure 11
Figure 12
X.
CALIBRATION INTERVALS
There is no simple answer as to how often one should calibrate an
instrument. The Ultrameter is designed to not require frequent
recalibration. The most common sources of error were eliminated in the
design, and there are no mechanical adjustments. Still, to ensure
specified accuracy, any instrument has to be checked against chemical
standards occasionally.
A. Suggested Intervals
On the average, we expect calibration need only be checked monthly for
the Conductivity, RES or TDS functions. The pH function should be
checked every 2 weeks to ensure accuracy. Measuring some solutions
will require more frequent intervals.
B. Calibration Tracking Records
To minimize your calibration effort, keep records. If adjustments you are
making are minimal for your application, you can check less often.
Changes in conductivity calibration should be recorded in percent.
Changes in pH calibration are best recorded in pH units.
Calibration is purposely limited in the Ultrameter to ±10% for the
conductivity cell because more than that indicates damage, not drift.
Likewise, calibration changes are limited to ±1 pH unit because more than
that indicates the end of the sensor lifetime, and it should be replaced.
C. Conductivity, RES, TDS Practices to Maintain Calibration
1.
Clean oily films or organic material from the cell electrodes with
foaming cleaner or mild acid. Do not scrub inside the cell.
2.
Calibrate with solutions close to the measurements you make.
Readings are compensated for temperature based on the type
of solution. If you choose to measure tap water with a KCl
compensation, which is often done (ref. An Example, pg. 30),
and you calibrate with 442 solution because it is handy, the
further away from 25°C you are, the more error you have. Your
records of calibration changes will reflect temperature changes
more than the instrument’s accuracy.
3.
Rinse out the cell with pure water after making measurements.
Allowing slow dissolving crystals to form in the cell contaminates
future samples.
4.
For maximum accuracy, keep the pH sensor cap on tight so no
23