© 2017 Proceq SA
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© 2017 Proceq SA
3. Optional Settings
After selecting each of the optional settings defined below you will be asked to confirm or cancel
the setting.
3.1 Units
NOTE! It is only possible to select a unit other than the default “R” if a UCS or E-modulus
conversion curve has been selected. (See chapter 3.3)
If weathering grade is selected as the statistics method, then R is automatically set as the
default value.
Select the units for UCS uniaxial compressive strength or mod-
ulus of elasticity estimates.
R, N/mm2, MPa, GPa, psi,
NOTE! Due to the difference in order of magnitude,
GPa can only be selected for modulus of elasticity
conversions.
3.2 Statistics
Select a preset statistics method
WG, ASTM, ISRM, Median, Mean, User
The WG (weathering grade) method requires two impacts to be carried out on exactly the same test
location. The difference between the two impact values is calculated and displayed. Please refer to
the ISRM guideline for a complete explanation.
The ASTM D 5873 method requires 10 impacts from which a mean is calculated. Individual impacts
that differ by more than 7 from the calculated mean are discarded and a new mean is calculated
from the remaining values.
If a conversion curve has been selected, tilting the instrument shows the UCS in the chosen unit.
The ISRM method requires 20 readings with no deletion of outliers. A series may be terminated pre-
maturely if any 10 subsequent readings differ by ±2. On completion the RockSchmidt calculates the
mean and the range. Once downloaded to a PC, RockLink also calculates the median and the mode.
If a conversion curve has been selected, tilting the instrument shows the UCS in the chosen unit.
Tilting again displays all impacts in descending order plus the maximum and minimum values.
The median method does not specify the number of impacts. The series can be terminated at any
time and the median is displayed as a result.
The mean method does not specify the number of impacts. The series can be terminated at any
time and the mean is displayed as a result.
User preset allows the operator to define his own statistics method, determining the number of
required impacts, how many outliers are deleted etc. This is done using the RockLink software.
(See chapter 9.7).
3.3 Conversion Curve
Conversion curves for UCS or E-modulus correlations must first be created in RockLink and up-
loaded to the RockSchmidt.
Scroll to the desired curve by ROLLING the hammer towards
you or away from you.
3.4 Correction Factor
Use for entering a correction value if the hammer does not fulfil the calibration check and there is no
immediate possibility to replace the impact spring. (See chapter 2.5 and 8).
The correction factor is calculated by dividing the specified value on the anvil by the average of ten
readings on the anvil.
e. g. Specified value on anvil = 91 R, rebound number measured on anvil = 88 R
Correction factor = 91/88 = 1.03
Tilt to the left of right to adjust the value.
The correction values may be between 0.75 and 1.25
NOTE! The uncorrected R-values are saved as part of the test result. The correction
factor is applied to the calculated average and can be posthumously corrected in
RockLink. (See chapter 9.1)
