Abstract: A method and device for sensing hole parameters while drilling a borehole, and transmitting the sensed data to a remote receiver. Data are transmitted in digital format as a series of audible binary pulses generated by a solenoid acoustically coupled to the drill pipe. In a preferred embodiment, data transmission occurs automatically during periods of drilling inactivity.

Abstract: A current controller interface accepts a variable voltage at its input and develops a current at its output which corresponds directly with the input variable voltage. Its apparatus is usually associated with a program controller as an input and a microscope which has a heated element as the output. The apparatus uses a control circuit which is coupled to a controllable resistance semiconductor device, which device has an output which varies in resistance in accordance with variation in input current. The output of the variable resistance device is coupled in series with the heating coil of the microscope, the power supply and current sensing resistor. The resistor develops a feedback voltage which is applied to the control circuit so that when a change in voltage is applied to the input the output from the current sensing element will change until it balances the current being applied at the input. When the balance occurs, no further change in output current will occur.

Abstract: The present invention relates to a program controlled apparatus for providing rapid calibration and update of sensor parameters in a push drill guidance apparatus which is remotely controllable from microprocessor circuitry. A special calibration program is set into non-volatile memory for coaction with the control processor to compute sensor parameters for storage and recall during normal programmed guidance operation.

Abstract: Strain gauges are attached to a drill pipe which is inserted into a drill pipe string to be used in a well. The strain gauges are connected to an electrical circuit containing devices for digitizing the electrical signals generated by the strain gauges in response to the detection of strain and for recording and retaining the digitized signals until the drill pipe string is extracted from the well. The electrical circuit provides a communication path through which the stored digitized data is transferred to an external device when the drill pipe string is extracted from the well.

Abstract: An intrinsically safe regulated power supply has an input connected to a source of power and an output connected to a voltage-limited diode. The output current is limited by having a current sensor placed in series between the output terminal of the regulator and the diode. The current sensor generates an output which is applied to a differential amplifier. The differential amplifier develops an output voltage which is proportional to the current passing through the current-sensing means. This voltage is converted to a corresponding frequency which forms pulses having a repetition rate proportional to the frequency from the voltage-to-frequency converter but having a constant width. Pulses are applied to output transistors which control the current through the primary of a transformer. An excessive output current will convert the pulses to a low repetition rate, drastically cutting the voltage which will prevent excessive current through the load.