CGEO-SG5
Rebar VW Strain Gauge 13
CGEO INTERNATIONAL LIMITED
Installation Manual
5. TROUBLESHOOTING
Maintenance and trouble shooting of Vibrating Wire Rebar Strain Gauges are confined to
periodic checks of cable connections. Once installed, the meters are usually inaccessible and
remedial action is limited.
Consult the following list of problems and possible solutions should difficulties arise. Consult
the factory for additional troubleshooting help.
Symptom: Strain Gauge Readings are Unstable
Is the readout box position set correctly? If using a datalogger to record readings
automatically are the swept frequency excitation settings correct? Channel B of the
BSIL-RO-VW readout can be used to read the Strain Gauge.
Is there a source of electrical noise nearby? Most probable sources of electrical noise are
motors, generators and antennas. Make sure the shield drain wire is connected to ground
whether using a portable readout or datalogger.
Check whether the connection of readout and strain gauge’s leads is well. Does the readout
work with another Strain Gauge? If not, the readout may have a low battery or be
malfunctioning.
Symptom: Strain Gauge Fails to Read
Is the cable cut or crushed? This can be checked with an ohmmeter. For the CGEO-SG5,
nominal resistance between the two gage leads (usually red and black leads) is /-10,
Remember to add cable resistance when checking (22 AWG stranded copper leads are
approximately 50ohm /km, multiply by 2 for both directions). If the resistance reads infinite,
or very high (megohms), a cut wire must be suspected. If the resistance reads very low (
＜
20
ohm ) a short in the cable is likely.
Does the readout or datalogger work with another Strain Gauge? If not, the readout or
datalogger may be malfunctioning.
