电磁探头的瞬变发射电流采集电路设计

Circuit Design to Acquire Transient Emission Current of Electromagnetic Probe

瞬变电磁仪器发射时向发射探头提供一定强度的脉冲电流信号,测量电路对探头的发射电流实时监测并把数据上传。所设计的电流采集电路利用了大功率电阻对发射电流信号进行取样,然后把电压信号输入放大器进行减法、加法运算得到可表征电流强度的电压模拟信号。因电路设计把数字地和模拟地进行隔离,又采用线性光耦变送模拟信号,最终输出到单片机处理器A/D端口,进行软件编程实现了处理器对电流信号的实时采集。电流采集电路进行了实验测试并验证此种技术方案可行,在对电磁探头进行发射性能检测时可利用此电路记录发射电流。另外,在研制瞬变电磁测井仪器时,此项电流信号采集技术可向仪器的电路方案设计提供一定的科学借鉴。

A significant pulse current signal was provided to the transmit probe at the time of the transient electromagnetic （ TEM） instrument transmits signal.The emission current was measured by measurement circuit of the probe in real-time and data was uploaded.The high power resistor was used to sample the emission current signal in the design of the current acquisition circuit,and the voltage signal was input to the amplifier to achieve the subtraction and addition operations.Then the voltage analog signal was got which can be characterized by the current intensity.Due to the digital and analog ground were isolated in the circuit design,and the linear optocoupler was used to transmit the analog signal.Finally the analog signal was output to the microcontroller processor＆#39;s A/D port,and it was acquired in the processor by software programming in real-time.Experiments were carried out to test current acquisition circuit and it was verified that this technology was feasible.The emission properties of the electromagnetic probe can be detected in use of the circuit to record the emission current parameter.In addition,the current signal acquisition technology can provide a scientific reference to the circuit design during developing of the transient electromagnetic logging instrument.