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SIM922 & SIM923 Diode and Platinum RTD Temperature Monitors

  • Four channels with independent displays
  • 1.4 K to 475 K with silicon diodes
  • 20 K to 873 K with platinum RTDs
  • Memory for 4 calibration curves plus standard curve
Specifications

The SIM922 Diode Temperature Monitor and the SIM923 Platinum RTD Monitor are designed to measure four sensors simultaneously. Based on the modular SIM platform, they provide high performance, multiple channel capability in a small footprint.

SIM922

Each of the four channels in the SIM922 has an independent, precision 10 µA current source to provide sensor excitation. Measurement results can be displayed in either kelvins or volts.

SIM923

The four channels in the SIM923 have independent, stable 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 SIM922 and SIM923 employ four-wire measurement circuits (±I excitation leads, ±V sense leads) making the measurements insensitive to series lead resistance.

The four channel excitations are independently controlled and do not switch on or off when the readout is advancing between channels. Sensor excitations can be disabled to reduce power dissipation at sensitive cryogenic stages. This also accelerates readings in the remaining enabled channels. Measurements are performed at rates up to four readings per second.

A factory-standard calibration curve is built in for each model. In addition, each channel has non-volatile memory to store a 256-point custom calibration curve to convert sensor units (V or Ω) to temperature units (K).

SIM922 & SIM933 Specifications

SIM922 SIM923
Number of inputs 4 4
Sensor type Silicon diode Platinum RTD, other RTDs
Measurement type 4-wire 4-wire
Excitation 4 constant current sources 4 constant current sources
10 µA ± 0.01 %,
±5 ppm/°C		 1.0 mA ± 0.1 %,
±5 ppm/°C
Sensor units Volts Ohms
Input range 0 V to 2.5 V 0 Ω to 1400 Ω
Calibration curves 1 standard, 4 user-defined curves, 256 points each DIN 43760, 4 user-defined curves, 256 points each
Temperature range Sensor dependent,
1.4 K to 475 K (typ.)		 Sensor dependent,
20 K to 873 K (typ.)
Display resolution 4 digits 4 digits
Interface resolution 1 µV 1 mΩ
Measurement res 1.2 µV rms 1.2 mΩ rms
Measurement acc, (23±1) °C 20 µV + 0.01 % of reading 5 mΩ + 0.01 % of reading
Temperature coefficient ±5 ppm/°C ±5 ppm/°C
Common Specifications
Operating temperature 0°C to 40°C, non-condensing
Interface Serial via SIM interface
Connectors:
Two DB9 (female) 4 wire measurement + ground (Ch 1 & 2)
4 wire measurement + ground (Ch 3 & 4)
DB15 (male) SIM interface
Power Power supplied by the SIM900 Mainframe, or optionally by a user-supplied DC power supply (±15 V and +5 V)
Dimensions 1.5" × 3.6" × 7.0" (WHL)
Weight 1.4 lbs.
Warranty One year parts and labour on defects in materials and workmanship