HOBO Dissolved Oxygen Logger (U26-001) Manual
2
Logger Components and Operation
Communications Cap/Lanyard.
This removable cap protects
the optical communications window. An LED in the
communications window of the logger confirms logger
operation. When the logger is logging, the LED blinks once
every four seconds. The LED also blinks when the logger is
recording a sample. When the logger is awaiting a start because
it is configured to start “At Interval,” “On Date/Time,” or “Using
Coupler,” the LED blinks once every eight seconds until logging
begins. See
Connecting the Logger to a Computer or
Waterproof Shuttle
for details on using the communications
window.
Mounting Hole.
Use the hole on the communications cap to
mount the logger. See
Deploying the Logger
for more
information.
Alignment Notch for Coupler.
Use this notch to align the
coupler when communicating with the logger. See
Connecting
the Logger to a Computer or Waterproof Shuttle
for more
information.
DO Sensor.
This optical sensor measures dissolved oxygen using
RDO® Basic Technology. It is shipped with a red dust cap that
must be replaced with a green sensor cap that lasts for six
months plus a one-month grace period. See
Installing the
Sensor Cap
for more details.
Protective Guard.
This removable guard protects the DO
sensor. Unscrew it to install or replace the sensor cap as
needed. See
Installing the Sensor Cap
for more details.
Temperature Sensor.
This built-in sensor (not visible in
diagram) measures temperature.
WARNING:
This logger can be damaged by mechanical
shock. Always handle the logger with care. The logger may be
damaged if it is dropped. Use proper packaging when
transporting or shipping the logger.
Do not attempt to open the logger case or sensor housing.
Disassembling of the logger case or sensor housing will cause
serious damage to the sensor and logger electronics. There are
no user-serviceable parts inside the case. Contact Onset
Technical Support at 1-800-LOGGERS (1-800-564-4377) or an
authorized Onset dealer if your logger requires servicing.
Installing the Sensor Cap
The logger ships with a replaceable sensor cap that provides six
months of continuous use. Once the cap is initialized, an
internal clock within the logger will count down until the sensor
cap expiration date. When the sensor cap expires, you will need
to replace it with a new cap (U26-RDOB-1
).
The sensor cap is
intended for six months of actual deployment, but the
expiration date is seven months from the date the cap was
initialized. This allows for any time needed between launching
the logger and physically deploying as well as extra time in case
you are not able to get the logger after exactly six months of
deployment. To install the sensor cap:
1.
Unscrew the protective guard covering the DO sensor (see
diagram at left).
2.
Remove the red dust cap that protects the sensor during
shipping.
3.
Take the green sensor cap out of the canister.
4.
With the flat part of the DO sensor pointing down and the
the green sensor cap oriented with the arrow up, slide the
sensor cap over the sensor until it snaps in place. The cap
should be snug against the logger housing without any gaps.
5.
Screw the external protective guard back on until tight.
IMPORTANT:
The sensor cap expires 7 months (to the day)
after it has been initialized. The logger will record a value of -
888 mg/L at each logging interval after the cap has expired.
Initialization occurs automatically when the cap is installed
while the logger is logging. You can also initialize it from the
Status window in HOBOware or when using the Lab Calibration
tool. To see when the sensor cap expires after being initialized,
check the Status in HOBOware for the expiration date. The cap
also has a shelf life; check the “Install By” date printed on the
canister.
Connecting the Logger to a Computer or
Waterproof Shuttle
To connect the logger to a computer, use either the Optic USB
Base Station (BASE-U-4) or HOBO Waterproof Shuttle (U-DTW-
1) with a coupler (COUPLER2-C). To launch and read out the
logger in the field, use one of these three methods:
•
Laptop computer with Optic USB Base Station (BASE-U-4)
and coupler (COUPLER2-C)
•
HOBO Waterproof Shuttle (U-DTW-1, Firmware Version
3.2.0 or later) and coupler (COUPLER2-C)
Temperature Sensor
(Inside Logger Housing)
Mounting
Hole
Communications Cap/Lanyard
Alignment Notch
for Coupler
Protective Guard
DO Sensor
DO sensor, flat
side down
Sensor cap with arrow
positioned up; slide over DO
sensor until it snaps in place
