RH Systems Thermometer 273
- Dual Range, Dual Current Source
- Full Current Reversal
- Graphical Display, Full Color Touch Screen
- Enter & Store Probe Coefficients
- Time Stamped Data Logging
- 273 Specifications
The 2-channel digital thermometer is designed for stable, high precision temperature measurement over the range of -200 to +660įC. To further enhance stability, the measurement electronics are encapsulated in a constant temperature oven.
Each channel of the 273 has two distinct measuring ranges (0-100 ohms and 0-400 ohms) and associated current sources (1 mA and 300 uA respectively) allowing both 25 and 100 ohm nominal PRTs to span the full range of the Delta-Sigma A/D converter. This current source/range selection allows the system to maintain high resolution regardless of the PRTís nominal value.
Employing a full reversal current source, the 273 eliminates polarity sensitive errors normally inherent in DC measuring techniques. Accuracy is further enhanced by referencing all measurements to an internal reference resistor placed in series with the PRT to be measured. With this resistance ratio technique, the 273 accurately determines the probe resistance independent of the current source accuracy.
View your data numerically or graphically at any time. The color touch screen simplifies the user interface. Select parameters, change graph scaling, enter probe coefficients, and configure the system; all from the front panel.
Enter your probe coefficients in ITS-90 format (the 273 even includes ITS-90 sub range 5) or use either the abc or αδβ coefficients of the Callendar - van Dusen equation. For standard industrial probes, pre-programmed IEC-751 standard coefficients are also selectable. Once entered, store the probe configuration in one of 10 memory locations for later retrieval and use. Each probe can be identified with a serial number and a short description.
With the large on board flash memory, the 273 can log tons of time stamped data with user selectable intervals from one second to several hours. This feature is great for unattended remote measurements and for creating a digital record of probe calibration data. Download the data to a PC at any time using HyperTerminal or any other simple terminal emulator program.
All 273 Thermometers include bi-directional RS-232 communications capability. You can retrieve readings in real time, download previously logged data, modify probe coefficients, change channel configurations, and more. The protocol is straight forward, intuitive, and powerful.