SIM922 & SIM923 Diode and Platinum RTD Temperature Monitors
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.
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.
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.
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
|Number of inputs||4||4|
|Sensor type||Silicon diode||Platinum RTD, other RTDs|
|Excitation||4 constant current sources||4 constant current sources|
|10 µA ± 0.01 %,
|1.0 mA ± 0.1 %,
|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.)
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|
|Operating temperature||0°C to 40°C, non-condensing|
|Interface||Serial via SIM interface|
|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)|
|Warranty||One year parts and labour on defects in materials and workmanship|