Introduction - Geokon LC-2x4 Instruction Manual

1. INTRODUCTION

Model 8002-4, LC-2x4, 4-Channel Datalogger is a low cost, battery powered, easy to use
measurement instrument, designed to read up to four vibrating wire sensors equipped with
thermistors.
The 320K standard memory provides storage for 10666 data arrays. Each array consists of an
optional datalogger ID string (16 characters maximum), a timestamp consisting of the year, date
(Julian day or month/day format), time (hhmm or hours/minutes format) and seconds when the
reading was taken. Also included in the data is the internal 3V (or external 12V) battery voltage,
the datalogger temperature, the vibrating wire readings, the transducer temperature and the Array
number.
Internal math is calculated using 32-bit floating point notation (IEEE). Math operations on the
instrument readings, such as application of zero readings, gage factors (or calibration factors)
and offsets when using a linear conversion technique or polynomial coefficients when using the
polynomial conversion, provide outputs directly in engineering units. The dataloggers internal
configuration is defined through communication with a computer using the supplied RS-232 or
USB (or optional RS-485) interface cable. The datalogger is configured and monitored using
LogView, a Geokon proprietary Graphic User Interface (GUI) software application (See Section
2.5). The datalogger can also be configured and monitored via text-based commands with any
standard terminal emulator software, such as Microsoft Windows HyperTerminal
3).
The communication method for each model of the LC-2x4 is described below
8002-4-1: Communication with the LC-2x4 is implemented via the host computer's RS-232
COM port. See Section 2.5.6 for further information.
8002-4-2: Communication with the LC-2x4 is implemented via the host computer's USB 2.0
port. When connected to a computer via the USB port, the LC-2x4 appears to the
computer as a "virtual" COM port. The LC-2x4 datalogger also receives all of its
operating power from the computer, thus extending the internal 3V (or external
12V) battery life. When disconnected from the USB port, the datalogger
automatically switches to the internal 3V (or external 12V) battery pack. See
Section 2.5.7 for further information.
8002-4-3: Communication with the LC-2x4 is implemented via RS-485. This allows for
long communication cables (up to 4000') between the host computer and the LC-
2x4. The ability to network two or more LC-2x4 dataloggers together is also
available with this communication option. See Section 2.5.8 and Appendix F
Networking for further information.
All data, both readings and configuration, are stored in non-volatile EEPROM with a typical
storage life of 10 years (minimum). The internal temperature compensated real-time clock, used
to provide timekeeping and triggering of readings, is accurate to approximately two minutes per
year. The comma delineated ASCII output format allows for easy importing into popular
spreadsheet programs such as Lotus 1-2-3 or Microsoft Excel. See Appendix D for sample data
files.
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