BARTINGTON INSTRUMENTS
Page 50 of 61 OM1800/26
Ensure a magnetically quiet area is used:
An area chosen to perform the adjustment should be
examined using Scan mode first. A good set-up area has less than 0.5nT variation in magnetic
gradient over a 1.5m x 1.5m area. Ensure you face in one direction for this test as directional
errors will not yet have been removed. If readings are very high then the ground in the area may
have magnetic content and another location should be used.
Coarse/fine ranges:
The adjustment cycle varies depending on whether you have selected the
100nT or 1000nT range. If the process restarts at any point, it is because the set-up is being
repeated in an alternate range. It is important to know how the equipment works so it is not
misinterpreted as faulty behaviour.
100nT Range:
A set-up will be attempted in the 100nT range. If this fails then it will repeat
the process in the 1000nT range. If successful in the 1000nT range, one further set-up will
be attempted again in the 100nT range.
1000nT Range:
A set-up will be attempted in the 1000nT range. If this is successful then a
set-up will be attempted in the 100nT range.
High gradient readings:
If the equipment is showing abnormally high values and the surrounding
area is known to be magnetically quiet then there are several ‘fixes’ that can be attempted to
bring it back to a normal level. The gradiometer should initially be set to the 1000nT range for
these to work.
High Balance:
Lift the gradiometer as high as you can above the ground, or stand on a non-
magnetic object, when carrying out the set-up process. This will lessen the impact of any
ground signals and bring the level of magnetic field registered by the two sensors in each
gradiometer closer together.
Horizontal Balance:
This has a similar effect to the above test. Hold the gradiometer
horizontal for the duration of the set-up process in order to bring the values back into a
normal range.
Once these tests have been carried out, the Grad601 should then be set up once more in the
normal fashion, and will be more likely to be successful.
If these suggestions do not prove helpful, please contact Bartington Instruments at
support
@
bartington.com
for further assistance.
21.2. Datalogger
The program for the Grad601 is held in one non-volatile flash memory. Details of the operating
parameters, memory locations and data are held in separate sectors in the same memory chip.
In the unlikely event that the data concerning the operating parameters becomes corrupt the
system reset option can be used, allowing the processor to restart.
