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Section
1
Model
DRC-93C
plus or minus the least significant
tion
accuracy,
the
software
bit, which
for the
470
series
interpolation accuracy
and
the
sensor results in an uncertainty of
calculation
of
the
resistance
l m K
below 28K and
45mK
above
40K
results in an overall accuracy on
with a transitional region between
the order of
10mK.
these two temperatures. Therefore,
at temperatures below
28K,
the
These input option cards are easily
overall system accuracy, the sum of
installed by the user; thus, units
the instrument accuracy (1lmK) and
can be changed or upgraded to
that of
the calibration itself
satisfy changing requirements.
(Lake Shore
calibrations
are
typically better than 20mK within
The ample memory space provided in
this region) is
&
30mK. Above
28K,
the DRC-93C allows several response
system accuracy gradually moderates
curves to be stored in the instru-
to a typical value of
+75mK
above
ment.
Depending on the complexity
40K.
See the Lake Shore IDW
of the curves, up to 25 can be
Temperature
Calibration Service
programmed into the unit.
The
brochure for additional discussion
active curve is selected either
of calibration accuracy.
from the front panel or over the
The Model DRC-93C can also be used
with the
9220
input card which
The data for calibrated sensors can
handles both diodes and positive
be stored in the instrument as an
temperature coefficient metallic
8001
Precision Option or by the
resistors.,
i.e.,
platinum
or
customer via the front panel or
rhodium-iron resistors.
The DIN
remote interfaces.
These curves
curve
is
standard
within
the
can
contain
up
to
99
sensor
instrument
and
is
called
up
temperature data points.
With the
automatically unless
a positive
standard precision option format of
temperature coefficient precision
31
data points and an
1 8
character
option curve is selected
for that
information line, up
to twenty
input. The accuracy of the reading
curves can be stored.
is dictated by the sensor and its
conformity to the DIN curve.
The
Although data points are stored as
tolerance on these devices is given
a
table,
the
interpolation
on the technical data sheet for the
algorithm used
results
in
the
Lake Shore PLATINUM RTD's.
The
equivalent
of
a
high
order
combined accuracy of the instrument
Chebychev polynomial calculation in
and a calibrated resistor with a
the
converting
of
the
input
precision option is on the order of
voltage (or resistance) to tempera-
40mK
over the useful range of the
ture.
This is done by means of a
sensor (above
40K
for the plat-
proprietary algorithm developed at
inum)
.
Note that a precision
Lake Shore Cryotronics.
option i s required for a rhodium-
iron to read correctly in tempera-
An
averaging algorithm
can be
ture
.
selected to average up to ten
temperature readings.
This mode
The Model DRC-93C with the 9318C
eliminates noise within the system
germanium/carbon-glass input card
analogous to
averaging with
a
results in the most accurate system
digital voltmeter.
This averaging
below
50K
in temperature.
mode can be disabled from the front
sensors, a precision option is
panel or over the remote interface
required to read in temperature.
for a given input if the customer
Near
4K,
the overall accuracy of
prefers not to average readings.
the system, including the calibra-
1-2
COPYRIGHT 3/88
LSCI
remote interface.
For both
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