THERMOCOUPLE MODULE WITH WIRE RESISTANCE COMPENSATION
    1.
    发明申请
    THERMOCOUPLE MODULE WITH WIRE RESISTANCE COMPENSATION 审中-公开
    具有电阻补偿的热电偶模块

    公开(公告)号:US20150276498A1

    公开(公告)日:2015-10-01

    申请号:US14271633

    申请日:2014-05-07

    IPC分类号: G01K7/02

    CPC分类号: G01K7/021 G01K7/026

    摘要: An interface circuit is provided for an Input/Output (I/O) module in an industrial controller to compensate for voltage generated by a bias current in a thermocouple. During a calibration routine, the interface circuit supplies two known bias currents to a thermocouple and measures a voltage generated across the thermocouple as a result of each bias current. The measured voltages and known current values are used to determine the resistance value of the thermocouple leads. Using two known bias currents provides for an accurate measurement of the resistance value of the thermocouple leads when the thermocouple is generating a voltage corresponding to the measured temperature. Either the I/O module or the industrial controller may determine a voltage resulting from the bias current applied to the thermocouple during operation as a function of the measured resistance and compensate the voltage measured at the thermocouple leads to accurately determine the measured temperature.

    摘要翻译: 为工业控制器中的输入/输出(I / O)模块提供了一个接口电路,用于补偿热电偶中偏置电流产生的电压。 在校准程序期间,接口电路向热电偶提供两个已知的偏置电流,并测量由于每个偏置电流而在热电偶上产生的电压。 测量电压和已知电流值用于确定热电偶引线的电阻值。 使用两个已知的偏置电流可以精确测量当热电偶产生对应于测量温度的电压时热电偶引线的电阻值。 I / O模块或工业控制器可以确定在操作期间作为测量电阻施加到热电偶的偏置电流产生的电压,并且补偿在热电偶引线处测量的电压以精确地确定测量的温度。