A 4-digit display clearly and unambiguously shows the temperature
directly in Kelvin or Celsius with 0.1 degree resolution. At low temperatures
(under 30K) a SCALE EXPAND mode increases resolution to 0.01K for monitoring
trends and other relative temperature measurements. Absolute accuracy at
low temperatures is ±0.5K in either mode.
The silicon-diode input section of the DRC-84C is designed to use proven
Lake Shore DT-500 Series DRC-curve silicon-diode Sensors, which provide
measurement accuracy to ±0.5K at low temperatures. Accuracy can be increased
to better than ±0.1K through use of an individually calibrated sensor and
the DRC-Precision option to store the calibration. Any DT-500 Sensor can
be utilized in the latter case.
Lake Shore PT-100 Series 100-ohm Platinum RTD's are the ideal Sensors
for the platinum section. The standard response curve is based on 0.1%
interchangeability at
0
C and a temperature coefficient
(0
to 100°C) of
0.00835/°C.
the Lake Shore PT-100 Technical Data sheet. Custom calibrations are avail-
able and can be incorporated into the 84C via the DRC-Precision option.
°
The curve conforms to DIN standard 43760 and is published in
Since silicon-diode sensors can be damaged by exposure to temperatures
above 380K (DT-500DRC Sensors should not be used above 330K to prevent deter-
ioration of their epoxy seals), precautions are recommended in designing
systems for operation at higher temperatures. The preferred approach is to
have diode sensors installed only when the system is operated below room
temperature. Special software limits and error codes are generated if the
instrument is set to control a point above or below the silicon diode or
platinum sensor temperature limits (see Section 3.13
-
Table of Error Condi-
tions).
Control temperature is easily selected and read directly in Kelvin
or Celsius on front-panel digital thumbwheel switches and an adjoining scale-
select switch. The switches provide quick and constant display of the set
point with a resolution of 0.1K or C. Temperature controllability is a
function of system design; and performance is often better than
0.1
degree.
°
Both the gain and reset are variable, and can be set from the front
panel to enable the Controller to be precisely tuned to match the system
response over any temperature region. Ample gain and reset have been
designed in to assure fast response, low offset error, and high stability.
Two heater output levels are selectable on the DRC-84C.
Th
HI
mode
provides up to 25 watts of heater power while the LO mode limits output power
to a nominal 10 watts.
Five options are available with the DRC-80 Series of instruments. One
option
is
an analog signal which is proportional to temperature (DRC8-L/A).
This option has a sensitivity of 10 mV/K.
A second option is a ten-position switch (SW-10A) for multiple sensor
readout. This switch is a separate half-rack box which plugs into the Sensor
"B" position of the DRC-84C. The sensor selected is also identified via
digital interface of the DRC-84C, if present.
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