6
7
UpDating inStrUment anD prOBe Firmware
The instrument and probe firmware can be updated via ysi.com. There
you will find the new firmware files and instructions on how to update
the instrument and/or probe.
SenSOr maintenance - DiSSOlveD Oxygen
CLEANING ThE OBOD SENSOR CAP
The sensor cap should be kept clean since some types of fouling may
consume or produce oxygen which could affect the dissolved oxygen
measurements. To clean the sensor cap, gently wipe away any fouling
with a lens cleaning tissue that has been moistened with water. Do not
use a coarse towel or cloth or organic solvents to clean the sensor cap.
Using a coarse towel or organic solvent to clean the sensor cap may
cause permanent damage to the cap. For example, alcohol will dissolve
the outer paint layer and other organic solvents will likely dissolve the
dye in the cap. If the sensor cap is damaged, it must be replaced.
OBOD SENSOR CAP REPLACEMENT
When replacing a sensor cap, the Sensor Cap Coefficients must be
manually updated in the instrument. The instruction sheet shipped
with the replacement OBOD sensor cap includes the coefficients. See
the instrument manual for instructions on updating the Sensor Cap
Coefficients.
The frequency of sensor cap replacement is dependent on use. For
example, when the probe is powered on for approximately 4 hours
per day, 5 days a week, the sensor cap will need replaced about once
per year. If the probe is powered on more than this, the sensor cap will
need replaced more often.
To extend the sensor cap’s usable life, turn the instrument off when
not in use. For example, turn the instrument off over night, but not
between readings.
The sensor cap will also need replaced if it is damaged or cracked. See
the
Troubleshooting
section of this manual for instructions on how to
determine if the sensor cap needs replaced.
The replacement OBOD sensor cap is shipped in a humidified container
and the package should not be opened until the cap is needed for
use. Once the sensor cap has been installed on the OBOD probe as
described in this section, it is important to keep the sensor in a 100%
humid environment. Therefore, the OBOD sensor should be stored
in either a BOD bottle that contains a small amount of clean water
(approximately 40 ml) or in a BOD bottle that is filled with clean water
so the sensor cap is immersed in water, see
Sensor Storage for more
information. If the sensor dries out, refer to the rehydration procedure
in this manual for instructions on how to recondition the sensor cap.
Refer to Figure 2 below when following the instructions for replacing
the cap.
Figure 2.
Caution: Avoid touching the sensing end of the sensor
cap during the following maintenance procedures.
1. Remove the stir paddle from the probe by pulling it straight out.
2. Remove the old sensor cap from the probe by grasping the
probe body with one hand and then rotating the sensor cap
counterclockwise until it is completely free. Do not use any tools
for this procedure.
3. Carefully remove the o-ring and discard it. Do not use any tools to
remove the o-ring.
4. Clean the o-ring seat on the probe by first wiping off old o-ring
lubricant with a dry lens cleaning tissue. Next, clean away any
build-up with a water-moistened lens tissue and then dry with
another lens tissue.
5. Locate the o-ring supplied in the Sensor Cap replacement kit and
install it on the probe. Do not use any tools to replace the o-ring.
Be careful not to touch the clear optical DO sensor window. Any
fingerprints on the optical window will have to be cleaned off. After
installing the o-ring, ensure it is clean. If necessary, wipe clean with
a lens tissue.
O-ring
OBOD Sensor Cap,
shown here removed
from probe