Page 22 of 130
Operating instructions
4point light 10W (V 4.58)
The mapping mode is mainly developed for archaeological work and will enable the user
to perform high speed measurements in a two-dimensional grid.
▪
R
e
M
o
T
e (
RMT
)
In Remote mode (RMT) an external computer will control the instrument. This mode will
mainly be useful with active external electrodes.
▪
TOM
ography (
TOM
)
In tomography mode tomography data will be acquired with external active electrodes.
▪
MON
itoring (
MON
)
In monitoring mode time lapse data with either active electrode systems or a single 4-
electrode combination can be acquired.
Two other measuring modes
in the main menu are
:
▪
CONTACT
Under the menu item CONTACT the output voltage is estimated, which is necessary to
establish the preset constant output current at the AB electrodes. This voltage indicates
the quality of the coupling of the current electrodes.
▪
S
elf
P
otential (
SP
)
SP is used for the determination of the spontaneous potential at M and N (useful in case
of unpolarizable electrodes at M and N).
6.4 Calibration
There are
two possibilities
to calibrate the instrument:
▪
Offset calibration
▪
Full calibration
, this means calibrating the complete receiver transfer function
The instrument is delivered fully calibrated!
New
calibrations are recommended only
:
▪
in intervals of several months
▪
in case of operating the instrument under extreme temperature conditions
▪
in case of trying to determine very small voltages (of the order of < 5 microvolts)
at MN with high accuracy.
Repeatedly performing a
full calibration
is recommended
for high resolution IP
measurements.
For calibration instructions refer to
16.4 Calibration, page 22