HOBO® VOLT User`s Manual
Contents
1. senso fe ems Accuracy 10 mV 0 5 of reading NOTE The HOBO Volt logger cannot store the value 0 volts Input characteristics Input E and substitutes 10 mV instead 0 1 uA leakage max while disconnected 0 4 vA Q B while connected Connection points The HOBO Volt has four connections starting near the edge of the box A D input 0 to Note The sense line and analog input lines have 100K resistors in series with them to 2 5 volts analog input Sense line active high digital output Battery supply 3 5 volt help protect them from out of range inputs nominal output and Ground output Battery for unusual applications only Launch and recove ry The battery output line is not normally used It connects directly to the HOBO Volt Connect the HOBO Volt logger to the host computer using the appropriate interface cable logger s internal 3 5 volt battery which has a capacity of 370 mAHr Drawing current from CABLE PC 3 5 for a PC and CABLE MAC HOBO for a Macintosh When connecting the this line will reduce the life of the HOBO Volt logger s battery 3 5 mm communications cable to your HOBO Volt logger make sure that it is pushed completely into the connector You will now be able to communicate with the HOBO Volt logger using the host software See the software user s manual for launch details Recom The sense output line not normally used mended software BoxCar 3 6 or any version of BoxCar Pro At the end of th2. The coffee mug logger test You can make a simple battery using coffee a stainless steel spoon and a little tad bit of aluminum foil Connect the eae aluminum foil to the black lead from i your HOBO Volt and the yellow lead to S oB the spoon Place both the foil and the S spoon in the coffee making sure that o ods the foil and the spoon do not touch gt Your coffee is acidic enough to make a 0 70 weak battery The plot at the right gt shows the voltage output of the bes battery with time We attrib ute the initial drop to the 0 60 coffee s cooling 08 00 09 00 10 00 11 00 23Feb95 08 00 Coffee S N 429 Why does it rise with time and what causes the oscillation If you know the answers please tell us Battery Instructions In normal usage the 3 6 volt HOBO battery is expected to last two years although it is sug gested that you change the battery every year To change the battery remove the logger s cover Remove the old battery by pulling it straight away from the board To remove the high internal resistance that builds up when this kind of battery is not in use short the new battery for one second by touching the leads with a paper clip before installing it When the battery first makes contact the status LED on the board should blink brightly five times If it does not remove the battery wait ten seconds and try again Finally place the cover back on the HOBO Volt logger lining it up so that the LED shows
3. e average Reed E sy EA AA current drain of the HOBO Volt is about 20 wA and the sense line is Switch Time accu racy g 100 aaa only high for conan ean Sei during a oo Ground At room temperature the logger s idea of time can vary ES ae he Balt BeCOn Gn ver va ule BV erage CITEN E from the actual time by as much as one hour per year T 130 A A switch j eTe R ene Valea or about 1 yA and 100 ppm There is an additional temperature effect 200 correspondingly lower for longer intervals shown in Plot A 40 20 0 20 40 60 Temperature 72
4. e deploy This output line is high about 3 5 volts during the fifteen millisecond time that the ment reconnect your logger to the host computer for readout The HOBO Volt logger HOBO Volt takes a measurement and low at all other times This output can be used to communicates at 1200 baud Its cleverly optimized software allows a full 2K off load in turn on power to an external sensor only during a measurement thereby minimizing the only twenty seconds sensor s current drain The external electonics needed to turn on power to the sensor depends on the application Operating environment Your HOBO Volt logger will operate correctly within the An example using the Sense line temperature range 40 C to 75 C Do not expose to an Reed switches close in the presence of a strong magnetic field A environment where condensation will form on the logger Plot A Graph 1093 HOBO Volt can be used to monitor the switch closure using the 3 Sores Condensation will cause corrosion The logger s accuracy 100 Timebase dependence circuit shown at right When the switch is open the input signal 100K is specified within this range as well Continuous expo 5 Pana will follow the sense line voltage When the switch is closed it will Input sure to temperatures above 45 C will reduce the HOBO 51 EIAN stay at ground level The 100K resistor is not really needed since Volt logger s battery life 5 Of XA 4 A there is one on the inside of the HOBO Volt logger Th
5. through the intended spot on the label 1996 1999 Onset Computer Corporation Trademarks Onset HOBO StowAway StowAway TidbiT Optic Shuttle Optic Base Station Optic Coupler TidbiT Coupler and BoxCar are trademarks of Onset Computer Corporation Onset Computer Corporation 470 MacArthur Blvd Bourne MA 02532 Mailing PO Box 3450 Pocasset MA 02559 3450 8 00 AM to 5 00 PM EST Tel 1 800 LOGGERS 1 800 564 4377 Tel 508 759 9500 Fax 508 759 9100 E mail loggerhelp onsetcomp com Internet http www onsetcomp com D 1584 C MAN HV HOBO VOLT User s Manual Thank yOu for purchasing a HOBO Voltage logger The HOBO Volt was designed as Warn ing a general purpose voltage logger Its accepts inputs ranging from 0 volts to 2 5 DC volts Do not apply a signal to the A D input that is more than 0 2 volts lower than ground or 0 2 volts higher that the battery supply nominally 3 5 volts f Calibration Timing Diagram The HOBO Volt logger has no calibration adjustments The accuracy is guaranteed by Timing using precision parts To check for possible part failures or assembly problems each The input is active for a fifteen millisecond period p n HOBO Volt logger is tested for accuracy at eight different voltages to verify that they are during each measurement The actual A D reading within specifications occurs two milliseconds after the start of this period y see timing diagram at the right
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