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The SIM922A Diode Monitor and the SIM923A RTD Monitor continuously
read a single sensor and provide both digital and analog outputs.
Based on the modular SIM platform, they provide high performance
capability in a small footprint.
SIM922A
The SIM922A has a programmable, precision 10 µA current source
to provide sensor excitation. Results can be displayed in either
kelvins or volts.
SIM923A
The SIM923A has selectable 10 µA and 1 mA current sources
to provide sensor excitation. Sensor resistance is determined ratiometrically
with a half-bridge circuit consisting of the sensor and an internal
reference resistor. The current to the sensor can be reversed by
the user to test for any offset. Measurement results can be displayed
in either kelvins or ohms.
Common Features
Both the SIM922A and SIM923A employ four-wire measurement circuits
(±I excitation leads, ±V sense leads), making readings
insensitive to series lead resistance. Sensor excitations can be
disabled to reduce power dissipation at sensitive cryogenic stages.
Measurements are performed at five readings per second.
The scaled analog output (±10 V) produces a voltage proportional
to measured temperature, with a full-scale range from 10 K to 1000
K. A relative-mode button subtracts the last absolute reading prior
to scaling, to provide expanded resolution for temperature deviations.
The second (monitor) output is the buffered, low-noise raw sensor
voltage without any additional processing.
Either analog output may be coupled to the SIM960
Analog PID Controller for high-performance, closed-loop temperature
control.
A factory-standard calibration curve is pre-programmed for each
model. Non-volatile memory also permits storage of a 256-point custom
calibration curve to convert sensor units (V or Ω)
to temperature units (K).
Results are displayed on an easy-to-read, 4-digit LED display.
Full remote operation is available over the serial interface.
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