In-Situ TROLL 9500 Operators Manual - Manual (Page 87)

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TROLL 9500 Operator’s Manual 0095110 rev. 007 01/09
4. Thread the membrane module to the D.O. sensor.
Be sure the membrane does not leak. You should not see
any drops on the surface. There should be no visible air
bubbles.
5. Install and condition the sensor as described below. Then you’re
ready to calibrate.
INSTALL THE SENSOR IN THE MP TROLL 9500
The polarographic D.O. sensor will function properly only
when installed in port 2.
1. Remove the restrictor or Cal Cup from the front end of the MP
TROLL 9500. This allows access to the sensor block shown in the
drawing below.
2. Remove any moisture or dirt from the area around
port 2, then use the sensor removal tool to remove
the plug or sensor from port 2. Retain the plug for
future use.
3. Remove any moisture or dirt from the port connector
with a clean swab or tissue.
4. Check lubrication of the sensor o-rings.
TIP: The sensor o-rings require generous lubrication before
installation. New sensors will be lubricated at the factory. If
the o-rings appear dry, apply a silicone lubricant before installation.
5. Handling the sensor by the sides, not the tip, align the mark on the
side of the sensor with the mark on the port.
Avoid touching the membrane at the tip of the sensor.
Contaminants on the membrane can change its properties
and affect measurements.
6. Use the sensor insertion tool to press the sensor into the port until
you feel it dock with the connector at the bottom. When properly
inserted a small gap (width of the sensor removal
tool) remains between the widest part of the sensor
and the instrument body, for ease of removal.
7. Turn the sensor “on” and condition it, as described
next.
CONDITION A NEWLY INSTALLED SENSOR
Condition a new sensor, or one with a new membrane, as follows:
1. Fill and install the sensor as described above.
2. Connect the MP TROLL 9500 to a PC and establish a connection
in Win-Situ 4 or Pocket-Situ 4.
3. Select the MP TROLL 9500 in the Navigation tree. All installed sen-
sors will be displayed.
Powering of the D.O. sensor begins as soon as the software rec-
ognizes the D.O. sensor and displays it in the Navigation tree. This
starts the conditioning process.
TIP: If you plan to calibrate 100% D.O. in air, condition the
sensor in a moist environment at ambient pressure—the
loosely attached Cal Cup with a small amount of clean water is ideal.
If you will be calibrating 100% D.O. in water, condition the sensor dry.
We recommend that you allow the sensor to condition for 2-10 hours
before calibrating. Testing has shown that 10 hours of conditioning
yields very stable long-term performance.
TIP: It is not necessary to maintain the computer connection;
conditioning continues as long as the sensor is installed.
CALIBRATION
OVERVIEW
Several options are available for calibrating a polarographic sensor.
s
D.O., conductivity) at the same time with one convenient solution.
This is a 1-point 100% D.O. calibration in air at ambient pressure.
s
either in air (saturated with water) at ambient pressure, or in water
(saturated with air—for example, using a bubbler). The water
method is generally more accurate, as it better represents actual
field D.O. measurement conditions.
s
either in air or in water. 0% D.O. is calibrated in an oxygen-
sensor
removal
tool
sensor
insertion
tool
SECTION 13: DISSOLVED OXYGEN—POLAROGRAPHIC
Install polaro-
graphic D.O.
sensor here
Pressure/Turbidity
(or plug)
Temperature
alignment mark