| 摘要 |
The present invention refers to a portable electronic digital multichannel device for measuring temperatures with the help of copper-constantan thermocouples and allows for eight-channel sequential measurement of temperatures, that is, eight sites for fastening thermocouples which can be located in solid or liquid media. The functioning principle of the device is based on the phenomenon according to which the thermal electromotive voltage supplied by a thermoelectric circuit built with copper-constantan thermocouples is a function of the difference between the temperature of the measuring joint and that of the thermocouple ends connected to terminals on the panel at the rear of the device. The device unit consists of a set of eight thermocouples and the device for measuring the electromotive voltages. The block diagram of the device includes an electric clock (A) which represents the system's time reference, a channel selector (B) which ensures the operation of all inputs, an instrumentation amplifier (D) whose role is to symmetrise and amplify the input signal, a reference sensor (E) and a temperature reference (F) as well as an electronic voltmeter. Measurements are done by taking notice of the indications of the clock (A) simultaneously with the indication for the current channel and the temperature value for the respective channel. The temperature indication for the current channel remains unchanged and is stored in the memory while it is displayed; it is not perturbed by possible temporary temperature variations in the respective sensor.
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