levels. Saturation of the sensor is evident when the logger reads values of 100% RH
or greater. Like all RH sensors, repeated saturation from exposure to condensing
environments will lead to irreversible drift and eventually destroy the RH sensor. If
this happens, the logger will need to be returned to Onset Computer Corp. for
sensor replacement. The rate at which this degradation of the sensor occurs
depends on the harshness of the environment to which the sensor is exposed.
Condensing environments with temperatures above 30°C (86°F), exposure to salt
spray, ammonia vapor, or some other chemicals will accelerate the sensor
degradation.
Mounting considerations in wet environments
The HOBO Pro Temp/RH IS version should be mounted so that the RH sensor is
protected from water saturation. To prolong the life of your RH sensor, Onset
strongly recommends mounting the HOBO Pro Temp/RH IS logger (H08-032-IS)
face down in a protective housing such as the Solar Radiation Shield (Onset part #
RS1) or the Rain Shield (Onset part # RS2).
Readout
The HOBO data logger must be removed from the hazardous location for readout.
Reconnect the HOBO data logger to the interface cable, start the logger software,
select
Readout under Logger on the menu bar and the data will be displayed in a
graphical or tabular form. For a complete explanation on reading out your logger,
please refer to the logger software manual.
Selecting Channels and Resolutions
The HOBO Pro IS logger offers a choice of
standard-resolution (8-bit) or high-resolution
(12-bit) operation for its temperature
channel. High-resolution mode doubles the
amount of memory required by each
measurement, reducing the deployment time
for each interval setting, but dramatically
improving the temperature resolution and
accuracy. The high-resolution mode is not available for the RH channel. For high-
resolution mode select the sensor and "Added Resolution" on the channel that
follows it. For standard-resolution select only the temperature channel. “
Added
Resolution” should not be enabled unless the corresponding temperature channel is
enabled, otherwise the data will be invalid.
Data Archiving
The HOBO Pro Temp/RH IS logger preserves the data from up to seven
deployments preceding the current deployment. You will be able to retrieve data
from all eight deployments by using the archive reader function in the logger
software. (In some versions of the software it is a separate utility for Windows 95/
98/NT on the installation disk.) The reader will contact your logger, readout the last
eight deployments, display information such as the deployment number, start time,
end time, number of points and the description, and then allow you to select which
file(s) you would like to save. For more information on the archive reader function,
consult your logger software manual or the Archive Reader Utility readme.txt file.
This archiving feature provides backup of your measurements in the logger, giving
you another level of protection from accidental data loss.
Battery Life Specifications and Battery Level Indication
The battery level is displayed on the host computer
during Launch. For the HOBO Pro IS logger this will
display one of two states: 98% or 20%. The lowest
battery level that will be shown is 20%. Thus if the
battery status indicates 20%, the battery is
effectively dead and should be replaced immediately.
Launching the logger when the battery level
reads 20% risks data corruption and/or data
loss.
In normal usage the HOBO Pro’s battery can last
up to three years when used with an interval of 1
minute or greater. Battery life is very dependent
upon the sample interval and service temperature.
See Table 1 for approximate run times at various
intervals and service temperatures.
Table 1. Approximate Operational Battery Life for the HOBO Pro
Logging Interval
Operating Temperature
< 10 seconds
10 secs - 1 minute
1 minute – 1 hour
+40 - +50°C+ (104 - +122°F)
~ 3 - 6 months
1
/
2
- 1
1
/
2
years
1
1
/
2
- 2 years
+25 - +39°C (+77 - +102°F)
~ 3 - 6 months
1
/
2
- 2 years
2 - 3 years
< +25°C (< +77°F)
~ 3 - 6 months
1
/
2
- 2
1
/
2
years
2
1
/
2
- 3+ years
The above times are intended only as guidelines. For critical field
applications of long duration we recommend installing a fresh battery before each
deployment. We recommend replacing the HOBO’s battery and O-rings
simultaneously (Onset battery/service kit part #HP-BK includes battery, O-ring,
stainless steel self-sealing screw with O-ring, O-ring lubricant and jack cap.)
Changing or Accessing the Battery
The HOBO data logger must be removed from the hazardous location for changing
the battery. If you can, offload the logger before changing the battery. This will
ensure that no data will be lost (See Non-Volatile Memory). To change the battery,
open the case by removing the Phillips screw in the center of the back of the logger
and removing the stainless steel back plate. Remove the old battery and install the
new one. Be careful to put the battery in the battery holder with the correct polarity
(Diagram B).
In order to maintain the Intrinsically Safe rating, your logger
must use a Tadiran TL-5902 (3.6v 1.2Ah) battery, Onset part number HP-B.
The logger’s red LED will blink three times after the battery has been installed. If
you have difficulty seeing the LED flash, use the battery check in the Launch dialog
box of the logger software to verify the battery status.
Warning: Do not cut open,
incinerate, heat above +185°F (+85°C) or recharge the removed lithium
battery. Dispose per local regulations.
Measurement Specifications
Temperature - Each HOBO Pro Temp/RH IS logger
has an internal temperature sensor mounted inside the
front of the logger's case (Diagram A). The sensor
measures ambient air temperature over the operating
range of the logger; -30°C to +50°C (-22°F to +122°F)
with a response time of less than thirty-five minutes
(typical to 90%) in still air. The HOBO Pro Temp/RH IS
logger has a standard and a high-resolution mode
which is selectable in the logger's software. For
temperature accuracy and resolution specifications,
please refer to Plot B for standard-resolution mode
and Plot C for high-resolution mode. See “Selecting
Channels and Resolutions” for more information.
Relative Humidity - The HOBO’s relative humidity
sensor has an accuracy of ±3% over the range of 0 to
50°C (32 to 122°F). The relative humidity sensor
range is 0 to 100% RH. It can read up to 104.1% in a
condensing environment. While the sensor is
saturated, you will not get accurate readings. In
general, the RH response time is less than 5 minutes
typical to a 90% change (independent of temp). Drift
is less than 1% per year in normal operating
conditions (non-corrosive, non-condensing). An
additional temporary drift of up to 3% can occur when the average humidity is above
70%. Factory verification and tune-up service available. White RH sensor case may
yellow with exposure to light. This is not a problem.
Connecting the Communications Cable and Launching
A Starter Kit, which includes the appropriate PC
interface cable and software, is required to operate
your logger. The HOBO logger must be launched
before it is deployed in a hazardous location.
Unscrew the jack cap from the logger. You can store
it temporarily by pushing it onto the cap holder
(Diagram A). Connect the interface cable into the
3.5 mm jack on the logger and into a working serial
port on your computer. Install and start the logger's
software. Select
Launch... under Logger on the
menu bar and a launch dialog box will be provided.
For a complete explanation on installing the software
and launching your logger, please refer to the logger
software manual.
When launching a logger, the software defaults to the parameters specified the last
time the logger was launched. The factory default is to select all channels with high-
resolution mode for temperature measurements. See “Selecting Channels and
Resolutions” for details.
Operation Indicator
The HOBO data loggers have a red LED that blinks while they are logging. The
blinking LED is located inside the 3.5 mm jack and is only visible when the PC
interface cable and jack cap are removed (Diagram A). The LED blinks brightly at
every measurement, and weakly every two seconds if the interval between
measurements is longer than two seconds. Once you have verified the operation
of the logger, rescrew the jack cap, making sure there is no dust or dirt on the cap
that might compromise the integrity of the weatherproof seal. Hand tighten lightly.
The cap only needs to be snug. If it is overtightened it may require a pair of pliers
to unscrew.
Operation on Computers Equipped with a Power Conservation
Mode
Many newer computers, especially laptops, have a power conservation feature which
shuts the serial port off after a short period of time. If a HOBO or StowAway logger
is still connected to the serial port when this happens, the logger will shut off. To
resolve power conservation shut off of the serial port, BoxCar Pro 4.0, 4.1, and 4.2.x
customers should download the BoxCar Pro 4.3 or later upgrade patch. Similarly,
BoxCar 3.6 and 3.7.1 customers should download the BoxCar 3.7.3 or later upgrade
patch. Both are available for free on our website under Support and Upgrades,
Software Upgrades and Utilities. If you have an earlier version of BoxCar and you
would like to test to see if you will be affected by the power conservation feature do
the following. Using BoxCar, launch your logger from the computer that you are
testing. If you are using a laptop, it may behave differently when running off battery
versus running off the power plug; please test both. After launch, leave the logger
attached to the PC interface cable and watch the LED to see if it remains blinking.
When a logger is actively logging, the LED will blink faintly every 2 seconds. If the
power conservation is causing a problem, the LED will stop blinking within one
minute. When you are using a HOBO Pro logger, the LED is located under the PC
interface cable, and is not visible when the cable is plugged in. To test a HOBO Pro,
launch the logger to take readings at 10 second intervals. Leave the logger attached
to the interface cable for one minute. You can either remove the interface cable at
this point and check the LED status, or download the datafile to see how many
points were collected. If power conservation is causing the logger to shut off, you will
only see one data point in the file. If your computer has the power conservation
feature, you should download an upgrade patch as noted above.
Mounting Options
The HOBO Pro Temp/RH IS data logger has mounting tabs. Be careful not to stress
the case when using the screws to mount the logger to an uneven surface, as this
may crack the tabs. The supplied hook and loop tape can be stuck on the back of
your HOBO for mounting. Do not use double sided tape on the back of the logger for
mounting, as this could disturb the weatherproof seal when the logger is removed.
HOBO Pro RH Sensor Should not get Saturated
The RH sensor used on the HOBO Pro is among the best in its price range. It is
designed for normal outdoor environments with cyclical high and low humidity
Plot B
Temperature Accuracy and Resolution
Standard Resolution Mode
Plot C
Temperature Accuracy and Resolution
High Resolution Mode
5896-D MAN-HO8-032-IS
4/21/04, 8:02 AM
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