2
2. TAKING READINGS
Different gages have different frequency characteristics and the GK-401 has a 6-position
selector: five positions with specific functions and one general position for period
readout.
Generally, positions B, C, D and E are used for all Geokon gages. Position A is used to
obtain period of vibration readings for gages in the range of approximately 500 to 5000
Hz. The table in the readout lid instruction panel describes positions for specific model
numbers. Table 1 shows the model numbers, readout positions and pertinent information.
Display
Position
Geokon
Model No.
Display
Units
Excitation
Range
Gage
Factor
A All¹
Period in
µ
seconds²
450-6000 Hz
None
B 4210
4300BX
4400
4500
4600
4700
4800
4900
f
2
×
10
-3
(digits)
1500-3500 Hz
1.000
C 4000
µ
strain
450-1200 Hz
4.062³
D
4200
µ
strain
450-1200 Hz
3.304³
E 4100
µ
strain
1500-3500 Hz
0.391³
F 4300EX
f
2
×
10
-3
(digits)
2500-6000 Hz
1.000
Notes:
¹ General position for all gages; possibility of harmonics in 4000 and 4200 gages at very
low strain levels.
² The period readings can be very useful for greater resolution of strain measurements.
Also, measurements as low as 0.1
µ
strain can be made (see individual manuals).
³ Factor multiplies digits (f
2
×
10
-3
).
Table 1 - GK-401 Display Position vs. Geokon Model Number
To take readings the gage is connected via the patch cord to the readout, the readout
display is set to the proper position and the box is turned on. A reading will appear in the
display and should remain constant, plus or minus one digit. The readout will turn itself
off after approximately 4 minutes. The reading is updated once a second and the display
is updated only when the reading changes. Readings should be checked against
previously recorded data and any unusual data should be retaken and noted.
