Troubleshooting - Geokon LC-2x4 Instruction Manual

5. TROUBLESHOOTING

Listed below are a few commonly experienced problems and remedial action. Contact the factory
should a problem arise not explained herein or additional information be needed.
Symptom: Unit will not respond to communications
Wrong COM port selected.

The USB Drivers may not be properly installed. See Section 2.5, 8002-4-2 (USB) Driver

Installation.
If RS-232 or RS-485 communications are being used, the internal batteries of the

datalogger may be low, dead, or inserted incorrectly. Check the batteries and replace if
necessary. (Units manufactured before September 2018 were supplied with an aluminum battery
holder, which may need adjusting; refer to Appendix I.)
If RS-485 communications is being used, the

key sequence is not being sent. Refer to Appendix F – NETWORKING for further
<ENTER>
information.
Symptom: Vibrating wire gage measurement reads -999999.0
Using an ohmmeter, check connections to the vibrating wire gage leads. Resistance

should be between 90 and 180 ohms (pins A and B on the 10-pin connector, see Appendix B).
Remember to correct for cable resistance, which is approximately 50 Ω per km (14.7Ω per 1000
ft.) Multiply this factor by two to account for both directions. If resistance reads less than 100Ω,
the cable is probably shorted. If resistance reads infinite or in the megohms range, the cable is
probably cut.
Check the datalogger with another known good transducer. If it still reads –999999.0, the

datalogger may be malfunctioning.
Check that the proper gage type is selected (see Table 2 and Table 3).

Check that the transducer shield wire is not shorted to either the red or black wire.

Symptom: Gage measurement (analog or vibrating wire) reads -999999.9
A mathematical over-range has occurred. Check the magnitude of the reading, zero

reading, multiplier and offset. The result must be in the range of 1.0 × 10
Symptom: Vibrating wire gage reading is unstable
Is there a source of electrical noise nearby? Likely candidates are generators, motors, arc

welding equipment, high voltage lines, etc. If possible, move the datalogger and transducer
cables away from the power lines or electrical equipment.
Check if the proper gage type is selected (see Table 2 and Table 3).

Symptom: Thermistor measurement shows -99.9 degrees Celsius
Indicates open circuit to thermistor leads. Check connections from datalogger to

thermistor leads. If okay, check thermistor with ohmmeter. Appendix E details the resistance
versus temperature relationship.
<ENTER>, <ENTER>, #,
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datalogger address,
to 1.0 × 10 .
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