Analog Devices' CN0287 is a completely isolated, 4-channel temperature measurement circuit optimized for performance, input flexibility, robustness, and low cost. It supports all types of thermocouples with cold junction compensation and any type of RTD (resistance temperature detector) with resistances up to 4 kΩ for 2-, 3-, or 4-wire connection configurations. The RTD excitation current is programmable for optimum noise and linearity performance. RTD measurements achieve 0.1°C accuracy (typical), and Type-K thermocouple measurements achieve 0.05°C typical accuracy because of the 16-bit ADT7310 digital temperature sensor used for cold-junction compensation. The circuit uses a four-channel AD7193 24-bit sigma-delta ADC with on-chip PGA for high-accuracy and low-noise. Low leakage transient voltage suppressors (TVS) and Schottky diodes provide input transient and overvoltage protection. The SPI-compatible digital inputs and outputs are isolated (2500 VRMS), and the circuit is operated on a fully isolated power supply. Evaluate this circuit using the EVAL-CN0287-SDPZ circuit board and the SDP-B (EVAL-SDP-CB1Z) system demonstration platform controller board. The two boards have 120-pin mating connectors, allowing for the quick setup and evaluation of the performance of the circuit. The EVAL-CN0287-SDPZ board contains the circuit to be evaluated and the SDP-B controller board is used with the CN0287 evaluation software to capture the data from the EVAL-CN0287-SDPZ circuit board.
Isolated 4-Channel, Thermocouple/RTD Temperature Measurement System