InsiteIG MPA-48, Manual

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14
pH SENSOR
The pH/ORP sensors consist of two parts; the M50 Holder and the Electrode (M51 or M52). They
are shipped separately and must be assembled prior to installing the sensor into the process. The
pH/ORP electrodes must be properly seated in the pH/ORP holder to ensure reliable operation and
proper cleaning. This is achieved by first ensuring that there is silicone lubricant on the O-rings and seat
and then by screwing the electrode into the holder until the top of the electrode is even with the line
etched onto the jet clean boss.
NOTE: Installing a pH/ORP holder without a pH or an ORP electrode
properly seated will void the warranty.
Calibration of pH electrodes have been greatly simplified, with ONE POINT or TWO POINT
calibration modes available.
pH buffers are special solutions which are used in the standardization or calibration of pH measuring
electrode systems. They are special because they have the ability to resist changing pH due to
contamination or dilution. The most common buffer dilutions are 4, 7 and 10 pH values. Other special
values can be purchased, and buffers for special biological and chemical applications are common.
pH buffers are supplied in either a powdered form to be mixed with distilled water or a premixed
liquid form. For pH buffers greater than 7, it is recommended that liquid buffer solutions be used
because they tend to be more accurate. However, liquid buffer solutions have a short shelf life (typically
3 months) which must be considered when ordering.
One Point Calibration Method
Select ONE POINT CAL from the setup menu. Submerge the sensor in the buffer solution. Press
the ENTER key. After the analyzer has acquired data, the pH value will be displayed. Use the UP and
DOWN arrow keys to change to the correct pH value and then press the ENTER key. The calibration is
stored in the non-volatile memory of the analyzer.
NOTE: This method of calibration only adjusts for asymmetry
in the electrode and thus should only be used in applications
where the process has a small range of pH values.
Two Point Calibration Method
Select TWO POINT CAL from the setup menu. Submerge the sensor in the first buffer solution.
Press the ENTER key. After the analyzer has acquired data, the pH value will be displayed. Use the UP
and DOWN arrow keys to change to the correct pH value and then press the ENTER key. Submerge the
sensor in the second buffer solution. Press the ENTER key. After the analyzer has acquired data, the
pH value will be displayed. Use the UP and DOWN arrow keys to change to the correct pH value and
then press the ENTER key. The calibration is stored in the non-volatile memory of the analyzer.
FACTORY DEFAULT
The Factory Default parameter allows the user to restore the sensor characteristic values of zero and
slope to the original factory settings.
TEMP. UNITS
The temperature units parameter allows the user to specify Celsius or Fahrenheit for the displayed
temperature units.
PASSCODE
The passcode parameter will allow the operator to limit access to the sensor setup parameters. The