Xylem 6-Series Multiparameter - Manual (Page 324)

Using Vented Level Appendix G
YSI Incorporated Environmental Monitoring Systems Operations Manual G-1
APPENDIX G USING VENTED LEVEL
Sondes that are equipped with level
sensors use vented cables. The vented level option eliminates errors due
to changes in barometric pressure. This is accomplished by using a special sensor that has been vented to the
outside atmosphere by way of a tube that runs up through the sonde and cable. The tube must remain open
and vented to the outside atmosphere to function. All storage caps must be removed and no foreign matter
can block the openings. Never expose the sonde or the cable to the atmosphere for more than a few minutes
without an active desiccant system in place. This prevents moisture from entering the vent tube.
Special field cables are used for the vented level. These cables have a vent tube that runs up the middle of the
cable. Your sonde has a stainless steel connector on the top of it. In the center of this connector is the vent
hole. When the cable is removed from the sonde, seal the sonde with the pressure cap provided with the
sonde, to keep it clean and dry. The field cable should also be stored in a sealed plastic bag with some
desiccant to keep it dry.
At the instrument end of every vented cable is a barbed fitting. This is to provide an attachment for a
desiccant system. One of the two desiccant systems should always be attached to the sonde while exposed to
the atmosphere to prevent moisture buildup in the vent tube. When dry and active, the desiccant is a distinct
blue color. When exhausted it turns to a rose red or pink color. The desiccant can be regenerated in an oven.
See Section 2.10, Care, Maintenance and Storage for the proper procedure.
Avoid bending the cables sharply to prevent the vent tube from kinking.
Two desiccant systems are available, a cartridge kit (YSI 6108) and a canister kit (YSI 6109). Either will
keep moisture from entering the vent tube. The desiccant cartridge kit mounts directly to the cable and is
intended for short-term applications. The desiccant canister contains a larger amount of desiccant and is
intended for long term deployment. The desiccant canister kit contains mounting brackets for mounting the
canister to a nearby structure. The length of time that the desiccant remains active depends on several factors
including heat and humidity.
When using vented level, you must enter altitude and latitude. From the sonde Main menu, select Advanced,
then 3-Sensor. Enter the altitude in feet and the latitude in degrees of the measurement site. These values
need to be accurate within 500 feet and 1 degree, respectively.
For best performance of depth measurements, users should ensure that the sonde’s orientation remains
constant while taking readings. This is especially important for vented level measurements and for sondes
with side mounted pressure sensors.
INSTALLING THE CARTRIDGE KIT
Barbed
Fitting
1/8” Tube
Adapter
Cartridge
1/4” Tube
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