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SERIES
9900
9000
SERIES
GAUSSMETERS
SECTION I V continued
Menu Operation/Gaussmeter
Programming
Prior to storing a digital correction factor for the lowest dc range, the Series-
9900 adjusts an offset suppression voltage at the input to the first
amplification stage. The unit then proceeds to generate and store a digital
correction factor for each dc range. If the probe offset is considered
excessive (>300 G/30 mT), or the probe is removed from the zero chamber or
disconnected during the zeroing process, an error will be reported and all
zero values generated to that point will be reset. In this case pressing the
ENTER pushbutton will restore normal menu operations.
Internally, ac and dc zeroing differs electronically. This difference is
transparent to the user, but
does
affect one aspect of machine operation.
The initial probe offset for the ac mode will affect the maximum reading that
can be reached in a given range. For instance, if the initial ac offset is
20.000 G and the probe is operated (after zeroing) on the 30 G range setting,
an overrange condition will occur when the field reading reaches 10.000 G
(30 G - 20.000 G = 10.000 G.) This limitation does not exist for the dc mode of
operation.
The internal zeroing values will remain in effect until the gaussmeter is turned
off or the probe is rezeroed.
NOTE: Whenever a probe is zeroed, all previously-generated relative values
will be reset and the relative function will be turned off for that channel (see
PROBE RELATIVE, Section IV-J).
IV-J PROBE RELATIVE
PROBE RELATIVE allows the probe to be "zeroed" in a non-zero magnetic
field. This field then becomes the reference point for all future
measurements. For example, if the relative field is +200.00 G and the probe is
afterwards inserted in a +250.00 G field, the displayed reading will be +50.00
G. A field of +150.00 G will be displayed as -50.00 G. Thus, the
RELATIVE
function can be useful for observing a variance around a given field density.
Like the PROBE ZERO operation, the PROBE RELATIVE function requires
the presence of an interface module and a probe. The relative values are
generated
only
for the mode (ac or dc) that is presently programmed for the
channel (via the MODE SELECTION menu).
PROBE RELATIVE
CHANNEL-I
CHANNEL-2
CHANNEL-3
HELP
MAIN MENU
RUN
FUNCTION
ON
OFF
RELATIVE VALUE
USE PREVIOUS
GENERATE NEW
Figure IV-I
PROBE RELATIVE Menu
Once a channel is selected on the menu the user has the choice of turning
the relative function ON or OFF for that channel. Selecting OFF returns the
gaussmeter display to actual field readings, rather than relative readings.
Selecting ON engages the RELATIVE function and allows the user to either
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