| 摘要 |
A thermocouple simulator system which is capable of generating a voltage equivalent to the EMF output of a thermocouple of a selected type at a specified sensing junction temperature. The system includes a keyboard which allows an operator to specify a sensing junction temperature, voltage, thermocouple type, reference junction temperature, and whether a pair of output terminals of the system perform as thermocouple alloy or copper. Using an operation program, a microprocessor calculates the thermocouple EMF using a stored temperature versus EMF polynomial function of the selected thermocouple type. The microprocessor then causes a voltage simulating the calculated EMF to be applied to the output terminals utilizing a reference voltage source, digital-to-analog converter (DAC), and output amplifier. When the wires connected to the output terminals are made of a different metal than the terminals, signals from temperature sensors in the output terminals are fed to the microprocessor through an analog-to-digital converter. The microprocessor then offsets the voltage simulating the EMF output to compensate for the thermocouple junction formed in connecting the wires to the output terminals. The system may also operate as a precision DC power supply with extremely low output impedance.
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