python系列009 操作仪器优化

使用万用表读取电压，保证进一步精度

    def read_voltage1(self):
        while (True):
            voltage_is1 = float(self.goal_dev.query("MEASURE:VOLTAGE:DC?"))
            time.sleep(2)
            voltage_is2 = float(self.goal_dev.query("MEASURE:VOLTAGE:DC?"))
            if abs(voltage_is1-voltage_is2) < 0.0001:
                break