Troubleshooting - Geokon 8800-2-1A Instruction Manual

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7. TROUBLESHOOTING

Listed below are a few commonly experienced problems and remedial action. Contact the factory
should a problem arise not explained herein, or if additional information is needed.
Symptom: Unit will not respond to communications
Wrong connection type, or incorrect port specified in Agent software.

The internal batteries of the Supervisor may be dead. Replace the batteries.
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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 C for
complete pin-out.) Remember to add the cable resistance at approximately 14.7Ω per 1000
ft. or 48.5Ω per km at 20 °C. Multiply this factor by two to account for both directions. If
the resistance is very high or infinite (megohms), the cable is probably broken or cut. If the
resistance is very low (<20Ω), the gage conductors may be shorted.
Check for a faulty or misconnected gage.

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 transducer cable away
from power lines and electrical equipment.
Symptom: Thermistor measurement shows -273.15 degrees Celsius
This indicates an open circuit to thermistor leads. Check connections from the Node or

Multiplexer to the thermistor leads. If okay, check thermistor with an ohmmeter.
APPENDIX D.8.3 details the resistance versus temperature relationship. It should read
between 10K ohms and 2.4K ohms (0 to +30 °C). If the thermistor is functioning correctly,
consult the factory to schedule the unit for repair.
Symptom: Node has weak communication
If the signal is consistently weak (indicated by red and green LEDs illuminated at the same time)
but not intermittently red, proceed with the installation. If the signal is frequently lost (red flash)
it will be necessary to improve it. Try to get the Node as high as possible, with plenty of clear
space around the antenna. Extending the sensor cable may enable moving the Node to a better
location. If the signal does not improve, a higher gain directional antenna may be necessary.
Contact Geokon for help.
Symptom: Node will not synchronize with network
If the red status light on a Node is flashing at 10-second intervals, it means the Node was once
connected to a network, but the network is not present now, or the Supervisor has been reset,
resulting in an equal, but not overlapping radio cycle. Be sure that the network is functioning in
deployment mode, (red light flashing every 10 seconds on the Supervisor,) then remove and
replace the batteries in the Node. The Node will now look for the changed network.