Gk-403 Readout Box (Obsolete Model); Connecting Sensors; Operating The Gk-403; Measuring Temperatures - Geokon 4850 Instruction Manual

N.a.t.m. style, v.w. concrete stress cells

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3.3 GK-403 Readout Box (Obsolete Model)

The GK-403 can store gauge readings and apply calibration factors to convert readings to

engineering units. The following instructions explain taking gauge measurements using Mode

"B". Consult the GK-403 Instruction Manual for additional information.

Connecting sensors with 10-pin connectors:

Align the grooves on the sensor connector (male), with the appropriate connector on the

readout (female connector labeled senor or load cell). Push the connector into place, and

then twist the outer ring of the male connector until it locks into place.

Connecting Sensors with Bare Leads:

Attach the GK-403-2 flying leads to the bare leads of a Geokon vibrating wire sensor by

connecting each of the clips on the leads to the matching colors of the sensor conductors,

with blue representing the shield (bare).

1) Turn the display selector to position "B".

2) Turn the unit on.

3) The readout will display the vibrating wire output in digits. The last digit may change

one or two digits while reading.

4) The thermistor reading will be displayed above the gauge reading in degrees

centigrade.

5) Press the "Store" button to record the value displayed.

If the no reading displays or the reading is unstable, see Section 5 for troubleshooting

suggestions. The unit will turn off automatically after approximately two minutes to

conserve power.

Each Vibrating Wire Stress Cell is equipped with a thermistor for reading temperature. The

thermistor gives a varying resistance output as the temperature changes. Geokon readout boxes

will read the thermistor and display temperature in °C automatically. To read the thermistor

using an ohmmeter, complete the following:

1) Connect the ohmmeter to the two thermistor leads coming from the stress cell. (Usually

white and green.) Since the resistance changes with temperature are large, the effect of cable

resistance is usually insignificant.

2) Look up the temperature for the measured resistance in Table 2 in Appendix B.

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