Taking Readings; Micro-6000 Datalogger; Embedment Strain Gauge Readout Positions; Gk-404 Readout Box - Geokon 4200 Series Instruction Manual

5.

TAKING READINGS

5.1 MICRO-6000 DATALOGGER

recommends the parameters in the table below when using strain
GEOKON
gauges with the MICRO-6000 datalogger or any other CR1000 based
datalogger. It shows the recommended gauge type selection and gauge factor
G entry to convert to microstrain. The table also lists the starting and ending
frequency settings for the excitation sweep when writing a program for the
CR1000 using the P28 vibrating wire measurement instruction.
Alternately, if a calibration sheet is supplied with the strain gauge, the exact
values can be calculated from the start and end frequencies of the calibration.
To maximize the stability and resolution of the sensor, a relatively narrow band
of excitation frequency should be selected. Calculate these settings by taking an
initial reading and then setting the starting frequency to 200 Hz below and the
ending frequency 200 Hz above.
MICRO 6000 Gauge Type 4200
Gauge Factor G Shown on calibration sheet
Start Frequency (P28) 4 (400 Hz)
End Frequency (P28) 12 (1200 Hz)

TABLE 2: Embedment Strain Gauge Datalogger Parameters

5.2 EMBEDMENT STRAIN GAUGE READOUT POSITIONS

The following table indicates the readout position detail for each strain gauge
model.
Model 4200/4200HT
Readout Position D
Display Units microstrain (με)
Frequency Range 450 1200 Hz
Mid Range Reading 2500 με
Minimum Reading 1000 με
Maximum Reading 4000 με

TABLE 3: Readout Positions

The following sections describe how to take readings using readout equipment
available from .
GEOKON

5.3 GK-404 READOUT BOX

The Model GK-404 Vibrating Wire Readout is a portable, low-power, hand-held
unit that is capable of running for more than 20 hours continuously on two AA
batteries. It is designed for the readout of all
and is capable of displaying the reading in either digits, frequency (Hz), period
(s), or microstrain (). The GK-404 also displays the temperature of the
transducer (embedded thermistor) with a resolution of 0.1 °C.
MODEL 4420 VIBRATING WIRE CRACKMETER | TAKING READINGS | 11
4200 6/7 4202 4204
D E A (Mode: digits)
readout units microstrain (με)
digits (f
400-1200 Hz 1400-3500 Hz 800-1600 Hz
2000 2500 με 1700 digits
1000 1000 με 650 digits
3000 4000 με 2750 digits
vibrating wire instruments,
GEOKON
4210/4212/4214
B
2 -3 2 -3
10 ) digits (f 10 )
1400-3500 Hz
6000 digits
2000 digits
10000 digits