CN213426165U - Power bus communication module of logging-while-drilling instrument - Google Patents
Power bus communication module of logging-while-drilling instrument Download PDFInfo
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- CN213426165U CN213426165U CN202022915978.4U CN202022915978U CN213426165U CN 213426165 U CN213426165 U CN 213426165U CN 202022915978 U CN202022915978 U CN 202022915978U CN 213426165 U CN213426165 U CN 213426165U
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Abstract
The utility model discloses a along with boring logging instrument power bus communication module, its "0" data received according to RS485 and QBUS digital communication interface modulate power bus in actual work. The modulated signal is a 250KHz alternating sine wave, the time length of which corresponds to the baud rate of the digital signal "0". When the digital communication interface receives data '1', the bus is not modulated, and when the digital communication interface does not send data, the bus is in a signal receiving state. The signal received on the power bus is restored into a 250KHz alternating current sinusoidal signal after passing through the signal receiving band-pass filter circuit. The signal is restored to be '0' and '1' of an analog signal after passing through a signal demodulation circuit, and then is sent to an RS485 or QBUS digital communication interface circuit after passing through a signal shaping circuit. Therefore, the purpose of communication by using the power bus is realized.
Description
Technical Field
The utility model relates to a logging while drilling instrument data transmission technical field, in particular to logging while drilling instrument power bus communication module.
Background
The communication between the short sections of the wireless logging-while-drilling instrument adopts RS485 double wires or QBUS single wires. In practical application, the MWD instrument string of the multi-core connector is combined with the resistivity short section, so that field construction is difficult during application, and poor contact is easily caused by the multi-core connector. It is relatively difficult to design improvements from a mechanical mounting perspective. Therefore, in order to further improve the efficiency of field work and further improve the reliability of the connection between the downhole instrument strings, the number of cores of the connectors connected between the instrument nipples needs to be minimized. The power bus communication module can well solve the existing use difficulty and technical difficulty under the technical conditions of the existing energy transmission mode and signal transmission mode. The power bus communication module can reduce the core number of the connector to two cores under the condition of not reducing the data transmission baud rate, and if the power negative end of the instrument short section adopts an instrument shell, the power supply and the communication between the instrument short sections only need to adopt a single-core connector.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide a along with boring logging instrument power bus communication module for along with boring power supply and communication between the logging instrument nipple joint.
In order to achieve the above object, the utility model adopts the following technical scheme:
a logging-while-drilling instrument power bus communication module comprises:
the single-ended flyback isolated voltage reduction circuit is used for providing a required power supply and is connected with a power supply bus;
a square wave source signal circuit for generating 250KHz square wave signals;
the input end of the square wave to sine carrier wave circuit is connected with the output end of the square wave source signal circuit and is used for obtaining a 250KHz square wave signal generated by the square wave source signal circuit and converting the signal into a 250KHz sine carrier wave signal for output;
one input end of the digital signal modulation circuit is connected with the output end of the square wave to sine string carrier wave circuit, the communication end of the digital signal modulation circuit is connected with a power bus, and the digital signal modulation circuit is used for converting a digital signal '0' into a modulation signal and modulating the modulation signal onto the power bus;
the signal isolation inductor is connected in series on the power bus and is used for enabling the modulation signal to exist on the power bus only and avoiding the load equipment from causing interference on the bus;
the input end of the signal receiving band-pass filter circuit is connected with the output end of the digital signal modulation circuit and is used for separating and outputting effective modulation signals on a power bus;
the input end of the signal demodulation circuit is connected with the output end of the signal receiving band-pass filter circuit and is used for restoring the effective modulation signal separated by the signal receiving band-pass filter circuit into an analog signal;
the input end of the signal shaping circuit is connected with the output end of the signal demodulation circuit and is used for shaping the analog signal output by the signal demodulation circuit;
and the RS485 and QBUS digital communication interfaces are communicated with the short sections of the logging-while-drilling instrument, the input ends of the RS485 and QBUS digital communication interfaces are connected with the output end of the signal shaping circuit, and the output ends of the RS485 and QBUS digital communication interfaces are connected with the other input end of the digital signal modulation circuit.
In a preferred embodiment of the present invention, the single-ended flyback isolated voltage-reducing circuit provides +5V and +2.5V power for the communication module of the power bus of the logging-while-drilling instrument.
In a preferred embodiment of the present invention, the square wave source signal circuit is composed of a low temperature drift crystal oscillator and a binary frequency divider.
In a preferred embodiment of the present invention, the square wave to sinusoidal carrier circuit is composed of a third order low pass filter circuit for filtering out useful 250KHz first harmonic components from the square wave.
In a preferred embodiment of the present invention, the digital signal modulation circuit is composed of an analog switch circuit.
In a preferred embodiment of the present invention, the signal isolation inductor is composed of a magnetic ring inductor.
In a preferred embodiment of the present invention, the signal receiving band-pass filter circuit is composed of a second-order active band-pass filter circuit.
In a preferred embodiment of the present invention, the signal demodulation circuit is composed of a half-wave amplification circuit and a third-order low-pass filter circuit.
In a preferred embodiment of the present invention, the signal shaping circuit is used after the signal demodulation circuit to make the output analog signal waveform regular and steep-edged digital waveform.
The utility model discloses a theory of operation is:
the power bus communication module of the logging-while-drilling instrument receives data from a short joint of the logging-while-drilling instrument from an RS485 or QBUS digital communication interface and modulates '0' in data flow to a power bus through a digital signal modulation circuit.
The power bus is connected with signal isolation inductors in series, and the signal modulated onto the power bus has high inductance to the inductors due to high frequency, namely the modulated signal only exists among the isolation inductors of each power bus communication module.
The modulated "0" signal is a 250KHz sinusoidal signal on the bus, with the time width of the signal corresponding to the baud rate of the digital signal.
The sine carrier signal of 250KHz is obtained by the square wave generated by the square wave source signal circuit after passing through the square wave to sine wave carrier circuit.
The square wave source signal circuit consists of a low-temperature drift high-temperature crystal oscillator and a binary frequency divider. The low-temperature-drift high-temperature crystal oscillator can be well adapted to temperature changes in the drilling process, and can provide a more stable sine carrier signal for the power bus communication module. Meanwhile, when the communication module is in a non-signal sending state, the signal receiving band-pass filter circuit receives signals from the power bus.
Because the voltage fluctuation of the whole string of logging-while-drilling instruments on a power bus is large when the logging-while-drilling instruments work, namely, clutter with other frequencies also exists on the bus besides useful modulation signals. These spurs interfere with the useful modulated signal. The signal receiving band-pass filter circuit has the function of enabling useful modulation signals to enter the signal demodulation circuit, and the correctness of demodulated data is improved.
Compare with current RS485 or QBUS bus method, the beneficial effects of the utility model are that: the utility model provides a along with boring logging instrument power bus communication module has reduced the core number of the indirect plug-in components of instrument nipple joint to still simplified the design of mechanical installation between the instrument nipple joint, improved along with boring the reliability of logging instrument in the work in the pit.
Drawings
FIG. 1 is a schematic structural diagram of a power bus communication module of a logging-while-drilling instrument according to the present invention;
fig. 2 is a schematic diagram of the digital signal modulation circuit of the present invention;
fig. 3 is a schematic diagram of the signal demodulation circuit of the present invention;
Detailed Description
In order to make the present invention more obvious and understandable, the present invention is further described below with reference to the accompanying drawings and the detailed description.
As shown in fig. 1, the utility model discloses a logging while drilling instrument power bus communication module contains the single-ended flyback isolated voltage reduction circuit 2 that provides required power for the communication module circuit, produce 250KHz square wave signal's square wave source signal circuit 3, a square wave that is used for obtaining 250KHz sinusoidal carrier signal changes sinusoidal carrier circuit 4, a digital signal modulation circuit 5 for converting digital signal "0" into modulated signal, a signal isolation inductance 1 for making modulated signal only exist on power bus, a signal reception band-pass filter circuit 6 for effective modulated signal on the separation power bus, a signal demodulation circuit 7 for reducing modulated signal into analog signal, a signal shaping circuit 8 for to the digital signal shaping after the demodulation, and with RS485 and QBUS digital communication interface 9 of the communication between each nipple joint of logging while drilling instrument.
The single-ended flyback isolated voltage reduction circuit 2 is connected with a power bus; and a +5V power supply and a +2.5V power supply are provided for the power bus communication module of the logging-while-drilling instrument.
The square wave source signal circuit 3 consists of a low-temperature drift crystal oscillator and a binary frequency divider, and the square wave-to-sine carrier circuit 4 consists of a third-order low-pass filter circuit and is used for filtering out useful 250KHz first harmonic components from the square wave. The input end of the square wave-to-sine carrier circuit 4 is connected with the output end of the square wave source signal circuit 3, and is used for obtaining the 250KHz square wave signal generated by the square wave source signal circuit and converting the 250KHz square wave signal into a 250KHz sine carrier signal for output.
One input end of a digital signal modulation circuit 5 is connected with the output end of the square wave to sine string carrier circuit 4, the communication end of the digital signal modulation circuit 5 is connected with a power bus, and the digital signal modulation circuit is used for converting a digital signal '0' into a modulation signal and modulating the modulation signal onto the power bus;
the signal isolation inductor 1 is composed of a magnetic ring inductor, is connected in series with the power bus, and is used for enabling the modulated signal to exist only on the power bus.
The signal receiving band-pass filter circuit 6 consists of a second-order active band-pass filter circuit, the input end of the signal receiving band-pass filter circuit is connected with the output end of the digital signal modulation circuit 5, and the signal receiving band-pass filter circuit is used for separating and outputting effective modulation signals on a power bus; the input end of the signal demodulation circuit 7 is connected with the output end of the signal receiving band-pass filter circuit 6, and is used for restoring the effective modulation signal separated by the signal receiving band-pass filter circuit 6 into an analog signal.
The input end of the signal shaping circuit 8 is connected with the output end of the signal demodulation circuit 7, and is used for enabling the output analog signal waveform to become a regular digital waveform with steep edges after the signal demodulation circuit 7.
The input ends of the RS485 and QBUS digital communication interfaces 9 are connected with the output end of the signal shaping circuit 8, and the output ends of the RS485 and QBUS digital communication interfaces are connected with the other input end of the digital signal modulation circuit 5.
As shown in fig. 2, the digital signal modulation circuit 5 is composed of an analog switching circuit; the 250KHz sine carrier signal sent by the square wave to sine carrier circuit 4 is connected to the S1B end of the ADG1436 (two-way single-pole double-throw SPDT analog switch IC3) after passing through the resistor R15.
When the TX signal is at a high level, the S1A terminal of the dual-path single-pole double-throw SPDT analog switch IC3 is connected to the D1 terminal of the dual-path single-pole double-throw SPDT analog switch IC3, and when the power bus has no carrier signal and no other noise signal, the D1 terminal of the dual-path single-pole double-throw SPDT analog switch IC3 outputs a 2.5V dc level through the resistor R17. If the carrier signal or the noise signal exists on the power bus, the D2 terminal of the dual-path single-pole double-throw SPDT analog switch IC3 also inputs a carrier signal or a noise signal. Since the TX signal terminal is at a high level, the TX2 signal is also at a high level, and the D2 terminal of the dual-path single-pole double-throw SPDT analog switch IC3 is connected to the S2A terminal, so the S2A terminal of the dual-path single-pole double-throw SPDT analog switch IC3 also outputs a carrier signal or a noise signal. This signal is connected to the next stage signal receiving band-pass filter circuit 6 through the capacitor C16 and the resistor R12. When the TX signal is low, the S1B of the dual-path single-pole double-throw SPDT analog switch IC3 is connected to the D1 terminal. At this time, the carrier signal at the S1B terminal of the dual-path single-pole double-throw SPDT analog switch IC3 is coupled to the power bus through the D1 terminal and the C22 terminal of the dual-path single-pole double-throw SPDT analog switch IC 3. In fig. 2, the resistor R32, the capacitor C28, the resistor R31 and the capacitor C29 mainly realize the function of delaying the phase of the signal. The signal of TX2 lags behind the TX1 signal, i.e., the switching state of the D2 terminal of the dual-path single-pole double-throw SPDT analog switch IC3 lags behind the D1 terminal, in order to reduce the effect between the output carrier signal and the input signal. Capacitor C23 in fig. 2 is the power supply bypass capacitor of the dual-path single-pole double-throw SPDT analog switch IC3(ADG1436 chip). Resistor R30 in fig. 2 is a weak pull-up resistor in order to reduce unwanted voltage fluctuations caused by switch turn-on delays. The diodes D3 and D4 are signal clamping diodes for clamping the signal coupled from the capacitor C22 between-0.7V and + 5.7V. CAR1TEST in FIG. 2 is a TEST point for a carrier signal on a circuit board.
As shown in fig. 3, the signal demodulation circuit 8 is composed of a half-wave amplification circuit and a third-order low-pass filter circuit.
The amplification factor formed by the operational amplifier A of the module IC8 (model AD8032AR) and the resistors R45 and R43 is-R43/R45. The operational amplifier operates in a positive single power mode. Namely, the operational amplifier can only output positive level, and the amplification factor is negative, so the operational amplifier only amplifies the negative half shaft of the sine modulation signal after passing through the band-pass filter. While the negative half-axis of the sinusoidal modulation signal contains a dc component. After the signal is amplified, the signal enters a first-order low-pass filter circuit consisting of a resistor R33 and a capacitor C34. The voltage divider circuit composed of resistors R51 and R53 and capacitor C47 achieves a reference level of 0.98V. The active low-pass filter circuit composed of the resistors R37 and R36 and the capacitors C38 and B operational amplifier amplifies the low-frequency part of the signal and does not amplify the direct-current component in the signal. And when the signal amplitude of the RD end is less than the reference level 0.98V, the output of the B operational amplifier is in a high level. When the amplitude of the signal at the end RD is greater than the reference level 0.98V, the output level of the B operational amplifier begins to drop, and the amplitude of the drop depends on the DC component in the signal and the value of the low-frequency component. The signal output by the operational amplifier B is further filtered by a resistor R46 and capacitors C45 and C46 and then enters a signal shaping circuit 8. In fig. 3, a capacitor C40 and a resistor R49 form a high-pass filter circuit, and the output signal of the band-pass filter is a direct current signal superposed with a sinusoidal alternating current signal. The dc component of the superimposed signal is null and the useful signal is the dc component of the negative half wave of the sine wave. In fig. 3, RIN1TEST and DEM1TEST are TEST points for output signals of the bandpass filter and output of the signal demodulation circuit on the circuit board, respectively.
While the present invention has been described in detail with respect to the above embodiments, it should be understood that the above description should not be taken as limiting the present invention. Numerous modifications and alterations to the present invention will become apparent to those skilled in the art upon reading the foregoing description. Accordingly, the scope of the invention should be limited only by the attached claims.
Claims (9)
1. A power bus communication module of a logging-while-drilling instrument is characterized by comprising:
the single-ended flyback isolated voltage reduction circuit is used for providing a required power supply and is connected with a power supply bus;
a square wave source signal circuit for generating 250KHz square wave signals;
the input end of the square wave to sine carrier wave circuit is connected with the output end of the square wave source signal circuit and is used for obtaining a 250KHz square wave signal generated by the square wave source signal circuit and converting the signal into a 250KHz sine carrier wave signal for output;
one input end of the digital signal modulation circuit is connected with the output end of the square wave to sine string carrier wave circuit, the communication end of the digital signal modulation circuit is connected with a power bus, and the digital signal modulation circuit is used for converting a digital signal '0' into a modulation signal and modulating the modulation signal onto the power bus;
the signal isolation inductor is connected in series on the power bus and is used for enabling the modulation signal to exist on the power bus only and avoiding the load equipment from causing interference on the bus;
the input end of the signal receiving band-pass filter circuit is connected with the output end of the digital signal modulation circuit and is used for separating and outputting effective modulation signals on a power bus; the input end of the signal demodulation circuit is connected with the output end of the signal receiving band-pass filter circuit and is used for restoring the effective modulation signal separated by the signal receiving band-pass filter circuit into an analog signal;
the input end of the signal shaping circuit is connected with the output end of the signal demodulation circuit and is used for shaping the analog signal output by the signal demodulation circuit;
and the RS485 and QBUS digital communication interfaces are communicated with the short sections of the logging-while-drilling instrument, the input ends of the RS485 and QBUS digital communication interfaces are connected with the output end of the signal shaping circuit, and the output ends of the RS485 and QBUS digital communication interfaces are connected with the other input end of the digital signal modulation circuit.
2. The LWD power bus communication module as recited in claim 1, wherein the single-ended flyback isolated voltage-dropping circuit provides +5V and +2.5V power to the LWD power bus communication module.
3. The LWD power bus communication module as recited in claim 1, wherein the square-wave source signal circuit is composed of a low-temperature drift crystal oscillator and a binary frequency divider.
4. The LWD power bus communication module as recited in claim 1, wherein the square-wave-to-sine-wave carrier circuit is composed of a third-order low-pass filter circuit for filtering out a useful 250KHz first harmonic component from the square wave.
5. The LWD power bus communication module of claim 1, wherein the digital signal modulation circuit is formed by an analog switching circuit.
6. The LWD power bus communication module of claim 1, wherein the signal isolation inductor is formed by a magnetic loop inductor.
7. The LWD power bus communication module of claim 1, wherein the signal receiving bandpass filter circuit is comprised of a second-order active bandpass filter circuit.
8. The LWD power bus communication module as recited in claim 1, wherein the signal demodulation circuit is composed of a half-wave amplifier circuit and a third-order low-pass filter circuit.
9. The LWD power bus communication module as recited in claim 1, wherein the signal shaping circuit is configured to output a digital waveform having a regular, steep edge and an analog signal waveform after the signal demodulation circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022915978.4U CN213426165U (en) | 2020-12-08 | 2020-12-08 | Power bus communication module of logging-while-drilling instrument |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022915978.4U CN213426165U (en) | 2020-12-08 | 2020-12-08 | Power bus communication module of logging-while-drilling instrument |
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| Publication Number | Publication Date |
|---|---|
| CN213426165U true CN213426165U (en) | 2021-06-11 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202022915978.4U Active CN213426165U (en) | 2020-12-08 | 2020-12-08 | Power bus communication module of logging-while-drilling instrument |
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