The present application generally relates to a seismograph with a sensor system that can provide both analog and digital information to a collection device.
A seismograph is an instrument that detects and records vibrations and movements of the ground and may also be used to detect and record air over-pressure events and/or sound waves. One use of a seismograph is to measure earthquake activity, but a seismograph may also be used for vibration and sound monitoring activities in other fields such as construction, mining, quarrying and demolition. For example, a seismograph can be used for vibration and sound monitoring during blasting operations, pile driving operations, construction equipment activity, environmental activity, and any other similar operation where a record of vibration and sound is needed.
A seismograph can include a sensor (may also be referred to as a seismometer) to measure vibrations and a collection device (or recording device) to process the information from the sensor. Typically, the sensor is either an analog sensor that provides analog information to the collection device or a digital sensor that provides digital information to the collection device. To provide for proper processing of the sensor information, the collection device has to be configured (or calibrated) for the sensor information to be provided by the sensor. The configuration process is typically a manual process that can be difficult and time-consuming. In addition, if the configuration process is not completed properly, the output data provided by the collection device may be inaccurate and/or unusable.
The present application generally pertains to a sensor system for a seismograph. The sensor system can incorporate a geophone design that combines the qualities of both digital and analog sensors, while maintaining separate analog and digital domains. The sensor system (geophone) has an analog output which can be digitized by a collection device of the seismograph at any resolution (number of bits) or number of samples (samples per second). By isolating the analog and digital sections of the sensor system, the sensor system can provide analog data to the collection device accurately and without interference from digital communications. The incorporation of the analog and digital sections into the sensor system enables the collection device to read digital information about the analog output of the sensor system from the digital section and then deactivate (or power off) the digital section before receiving analog information from the analog section. The collection device can use the digital information collected from the digital section for the processing of the analog data provided from the analog section of the sensor system. The digital information from the digital section permits the collection device to determine the appropriate sample rate and resolution for digitizing the analog data from the sensor system.
One advantage of the present application is that the output of the sensor system is not limited in bandwidth.
Another advantage of the present application is the use of the digital information can prevent the collection device from trying to collect information from the analog data in an invalid range and reduce or eliminate user error in configuring the collection device.
A further advantage of the present application is the ability to determine if the sensor is out of calibration and to make an assessment of how accurate the sensor may or may not be.
Other features and advantages of the present application will be apparent from the following more detailed description of the identified embodiments, taken in conjunction with the accompanying drawings which show, by way of example, the principles of the application.
Wherever possible, the same reference numbers are used throughout the drawings to refer to the same or like parts.
The collection device 102 can include at least one conventional processing element 162, which can incorporate processing hardware for executing instructions stored in the memory 155. As an example, the processing element 162 may include a central processing unit (CPU) or a digital signal processor (DSP). The processing element 162 can communicate to and drive the other elements within the collection device 102 via a local interface 165, which can include at least one bus. The collection device 102 can have a clock 169, which can be used to track time, and a power supply 171, which provides power to the components of the collection device 102. The power supply 171 can include an interface to receive electrical power from an external component, such as an electrical outlet or battery.
The collection device 102 can also have a communication module 166. The communication module 166 can include appropriate components to communicate (wired and/or wirelessly) with the sensor system 104 and/or a network, such as the Internet. In one embodiment, the communication module 166 can also include data ports, such as a USB (universal serial bus) port, Ethernet port, FireWire (IEEE 1394) port, Lightning connector port or other similar port, that can be used for coupling portable devices to the collection device 102 in order to transfer data from the collection device 102 to another computing device (either directly to the computing device, if portable, or via a portable memory device). Furthermore, an input interface 173, for example, a keypad, keyboard or a mouse, can be used to input data from a user of the collection device 102, and an output interface 176, for example, a printer, monitor, liquid crystal display (LCD), or other display apparatus, can be used to output data to the user.
As shown by
The configuration data 168 can be used by the A/D converter 175 in processing (or digitizing) the analog information (or data) communicated from the sensor system 104 to a predetermined number of bits of digital data corresponding to the analog data from the sensor. In one embodiment, the A/D converter 175 can digitize the analog data output from the sensor system 104 into digital data that can vary between a lower resolution value of about 8-bits (1 in 256) to a higher resolution value of about 24-bits (1 in 16777216). In another embodiment, the configuration data 168 can include data that controls the changing of the output resolution from the A/D converter 175 in order to determine very accurate readings over a reduced range in the analog data output by the sensor system 104. The resolution of the A/D converter 175 can be set based on the resolution of the analog data output by the sensor system 104. The maximum resolution for the A/D converter 175 is based on the maximum resolution of the analog data output by the sensor system 104. In other words, the resolution of the A/D converter 175 is limited to the resolution of the analog data that can be output by the sensor system 104.
In addition, the configuration data 168 can be used to establish the sampling rate of the analog data output from the sensor system 104 by the collection device 102 at a predetermined sampling rate. In one embodiment, the A/D converter 175 of the collection device 102 can sample the analog data output from the sensor system 104 at a rate that can vary between about 100 times per second and about 100,000 times per second. In another embodiment, the sampling rate of the A/D converter 175 can be one of five different sampling rates (e.g., 1024, 2048, 4096, 8192 or 16384 samples per second). The sampling rate used by the A/D converter 175 of the collection device 102 can be related to the ability of the collection device 102 to filter out any noise that is present in the analog data output from the sensor system 104 (i.e., pre-process the analog data) and in the ability of the A/D converter 175 to process the analog data. In one embodiment, the sampling rate can be inversely related to the resolution of the A/D converter 175, i.e., the greater the resolution of the A/D converter 175, the lower the sampling rate that can be used by the collection device 102.
In an embodiment, the A/D converter 175 can include 4 channels to receive analog data from the sensor system 104. The A/D converter 175 can designate 3 channels to receive analog data from a geophone and 1 channel to receive analog data from a microphone. However, other channel designations are possible in other embodiments. In another embodiment, the A/D converter 175 can have an additional 4 channels. The additional 4 channels of the A/D converter 175 can be used with a second geophone and microphone or with other sensors that measure different parameters (e.g., light, heat, pressure, etc.).
The sensor data 164 can include data and measurements from the corresponding sensor(s) of the sensor system 104. The sensor data 164 can include the digital data from the A/D converter 175 that converted the analog information (or data) from the sensor system 104 into a digital form. In one embodiment, the amount of sensor data 164 that can be stored in memory 155 can be limited by the amount space available in memory 155 and the resolution used to digitize the analog data output (i.e., the greater the number of bits used in digitizing the analog data, the fewer sensor data entries that can be stored). In another embodiment, the digital data from the A/D converter 175 can be processed using the configuration data 168 to improve the accuracy of the sensor data 164. For example, the configuration data 168 can include an offset or error value for the sensor system 104. The offset or error value can then be subtracted from the digital data value provide by the A/D converter 175 to correct for the error that may be present in the analog data from the sensor system 104. The offset or error value can be determined during a calibration process wherein the sensor system 104 is operated such that the output is supposed to be a zero. Any deviation of the output from zero during the calibration process can be used as the offset or error value when processing the digital data from the A/D converter 175.
The analog sensor(s) 110 can provide the analog signal(s) corresponding to the measured vibration, movement or sound (or to the measured temperature, pressure or light) to an analog section 116. After processing the analog signals from the sensor 110, the analog section 116 can provide the analog signals (i.e., the analog data) to a communication interface 112 that is coupled (e.g., wired or wirelessly) to the collection device 102. The communication interface 112 provides the appropriate interface with the collection device 102 to permit information and signals to be communicated between the collection device 102 and the sensor system 104. In one embodiment, the communication interface 112 can be separate from the analog section 116 and digital section 118 as shown in
The sensor system 104 can also include a power supply 114 and a digital section 118 that are coupled to the communication interface 112. The power supply 114 can be used to provide an appropriate power level to the analog sensor(s) 110 and to provide power to the components of the analog section 116. In one embodiment, the power supply can provide a sensor voltage of between about 3.3 VDC and about 5 VDC to the sensor(s) 110 to power the analog electronics inside the sensor(s) 110. In addition, the sensor voltage can be used to power the analog electronics of the analog section 116 inside the sensor system 104. In one embodiment, the power supply 114 can receive the corresponding sensor voltage and a reference voltage (discussed below) from the collection device 102 via the communication interface 112. The power supply 114 can then provide the sensor voltage and reference voltage to the sensor(s) 110 (e.g., a geophone and microphone) such that the sensor(s) 110 are using the same sensor voltage and reference voltage. In another embodiment, the power supply 114 can have an interface that permits the power supply 114 to plug into or otherwise interface with an external component, such as an electrical outlet or battery, and receive electrical power from the external component instead of the collection device 102.
The digital section 118 can provide information regarding the operation of the sensor system 104 and can be electrically (and otherwise) isolated from the analog section 116 (except for a common ground connection). The isolation of the digital section 118 from the analog section 116 can assist in maintaining the accuracy of the analog signals from the analog sensor 110 by limiting interference from the digital section 118.
The analog section 116 can also receive a reference voltage from the power supply 114 to set the steady state output voltage of the sensor 110. In one embodiment, the reference voltage can be one-half of the sensor voltage, but other values for the reference voltage can be used in other embodiments. The use of the reference voltage permits both positive and negative movements of the sensor(s) 110 (e.g., a geophone) to be able to determine the maximum range on both positive and negative displacement measurements. For example, if the sensor voltage is 3.3 VDC, then the reference voltage can be 1.65 VDC. The calibration circuitry 406 can apply a calibration voltage to the sensor 110 during a calibration process. The calibration voltage can be set to 0 VDC, the reference voltage or to the sensor voltage. The calibration voltage is used periodically to “zero” the sensor 110 or to determine if the sensor 110 is working properly. The calibration process can evaluate the sensor 110 by applying the reference voltage to the sensor 110 first, then applying 0 VDC, then further applying the sensor voltage and then the reference voltage again. The output of the sensor 110 can then be read by the calibration circuitry 406 to determine the zero point, full scale maximum and full scale minimum output of the sensor 110.
In one embodiment, the communication between the collection device 102 and the digital section 118 can occur using predetermined time slots for the collection device 102 and the digital section 118 to transmit data. Each time slot can be of a predetermined duration and can be 160 μs (microseconds) in one embodiment, but longer or shorter durations can be used for the time slots in other embodiments. For example, when the collection device 102 wants to obtain (or read) information from the digital section 118, the collection device 102 can provide a request having “1s” and “0s” to the digital section 118 to initiate communication between the digital section 118 and the collection device 102. Once communication has been initiated, the collection device 102 and the digital section 118 can transmit information to each other in their corresponding assigned time slot for communication. For example, the collection device 102 and the digital section 118 can alternate time slots for communication (e.g., one time slot for the collection device 102 followed by one time slot for the digital section 118). However, other time slot assignments could be used for communication (e.g., one slot for the collection device 102 followed by three time slots for the digital section 118).
The digital section 118 can include activate/deactivate circuitry 504 that can control the power for the digital section 118 based on signals received from the collection device 102 via the single connection. While the activate/deactivate circuitry 504 is shown separate from the interface circuitry 502 in
The activate/deactivate circuitry 504 can be used to initiate communication between the digital section 118 and the collection device 102 upon the receipt of a power signal from the collection device 102 via the single connection (e.g., the single connection is pulled “high”) and can terminate or end communication between the digital section 118 and the collection device 102 in response to the absence of the power signal from the collection device 102 via the single connection (e.g., the single connection is pulled “low”). In one embodiment, the activate/deactivate circuitry 504 can include a transistor configured with an open collector output pin that can be “powered on” by a power signal from the collection device 102 to permit the digital section 118 to send and receive data. A pullup resistor can be connected to the transistor to assist in the sending and receiving of digital data and to provide power to the digital section 118. The providing of the power signal over the single data connection allows the digital section 118 to be activated by the collection device 102 when the sensor configuration and calibration data 508 is needed by the collection device 102 and to be deactivated by the collection device 102 when the sensor configuration and calibration data 508 has been received by the collection device 102, thus allowing no digital error or noise to be induced into the sensor system 104 during analog sample times of the analog data output since the single connection is not being used for communications (i.e., there are no signals on the single connection).
In one embodiment, when the single connection is pulled high to power the digital section 118, the digital section 118 can output a signal to the collection device 102 informing the collection device 102 that sensor information is available. The collection device 102 can then send a series of digital data bytes to the digital section 118 to unlock and ask for sensor configuration and calibration data 508 stored in memory 506. The requested information is then provided from the digital section 118 to the collection device 102 over the single connection and is then stored as configuration data 168 in memory 155 of the collection device 102. In one embodiment, the digital section 118 can provide the series of digital data bytes to the collection device 102 using the transistor with the open collector output configuration and the pullup resistor as described above in the activate/deactivate circuitry 504. The collection device 102 can also use a similar open collector transistor and pullup resistor configuration to send and receive digital data bytes over the single connection. The pullup resistor can be used to assist in the sending and receiving of digital data and to power the transistor in the collection device 102. The pullup resistor can pull the output line low to send a “0” or leave the output line high to send a “1” to the digital section 118. The digital section 118 sends data back to the collection device 102 using a similar technique within the corresponding time slots as discussed above. The configuration data 168 can be used by the collection device 102 to determine what type of sensor 110 and what output scale is used by the sensor 110. Once all of the requested information has been received by the collection device 102, the digital section 118 is then powered off by driving the single connection low. In one embodiment, the single connection can be pulled high by a wide range of voltages (e.g., between about 3 V (volts) and about 5 V) for powering the digital section 118. By accepting a range of voltages, the digital section 118 can interface with collection devices 102 that provide voltages in the 3 V range or the 5V range.
The sensor configuration and calibration data 508 provided to the collection device 102 can enable the collection device 102 to determine the range of the sensor 110. For example, the collection device 102 can determine if the sensor 110 outputs 2 inches of movement or 10 inches of movement. In addition, the collection device 102 can determine the type of the sensor 110 and/or the engineering units used by sensor 110 from the sensor configuration and calibration data 508. The collection device 102 can also determine if the sensor 110 is configured for metric or imperial units. For example, the collection device 102 can be configured to receive analog data from the analog section 116 that corresponds to millimeters (mm) of movement or inches (in.) of movement based on the sensor configuration and calibration data 508 from the digital section 118.
In one embodiment, the digital information provided to the collection device 102 by the digital section 118 can be guaranteed to be accurate due by incorporating a CRC value into the sensor configuration and calibration data 508 being provided to the collection device 102. The CRC value can be used to check the validity of the data being provided by the digital section 118 to the collection device 102. In another embodiment, the digital information from the digital section 118 may be encrypted to prevent someone from being able to read and understand the information if the information is inappropriately accessed.
Once the collection device 102 has received of all the requested information from the digital section 118 and determined the form of the analog output, the collection device 102 can deactivate (or power off) the digital section 118 (step 606) by removing the power signal (or driving the connection low). When the digital section 118 has been deactivated, the collection device 102 can begin reading the analog data output from the analog section 116 (step 608). The analog section 116 can be activated (or powered on) in response to the deactivation of the digital section 118 or the analog section 116 can be previously activated (or powered) and not accessed by the collection device 102. As the collection device 102 receives the analog data from the analog section, the A/D converter 175 can be used to digitize the analog data (step 610) in accordance with the information from the digital section 118. The digitized data from the A/D converter 175 can then be stored as sensor data 164 in memory 155.
In one embodiment, the collection device 102 can have three monitoring modes for various situations: self-trigger, bar graph, and combo. In the self-trigger mode, the collection device 102 can monitor the digitized data from the A/D converter 175 for a threshold to be achieved (e.g., the corresponding sensor measurement represented by the digitized data exceeds a predetermined value). Once the threshold is achieved, a recording (i.e., the digitized data can be stored in sensor data 164) is made of the measurements from the analog sensor 110 (once converted to digital data by the A/D converter 175) for a predetermined number of seconds at the sample rate specified. In bar graph mode, the collection device 102 monitors the digitized data from the A/D converter 175 to determine the peak value of the digitized data within a predetermined time period. The collection device 102 can then save the peak value for the time period as sensor data 164. The interval (how often a value is selected from the samples) and period (how often the selected values are used to produce a peak value by determining the interval with the highest selected value) can be set by the user of the collection device 102. Combo mode can be a hybrid of the bar graph mode and the self-trigger mode. In combo mode, the collection device 102 operates similar to bar graph mode, but switches to self-trigger mode when the digitized data achieves the threshold.
Although the figures herein may show a specific order of method steps, the order of the steps may differ from what is depicted. Also, two or more steps may be performed concurrently or with partial concurrence. Variations in step performance can depend on the software and hardware systems chosen and on designer choice. All such variations are within the scope of the application. Software implementations could be accomplished with standard programming techniques, with rule based logic and other logic to accomplish the various connection steps, processing steps, comparison steps and decision steps.
It should be understood that the identified embodiments are offered by way of example only. Other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the embodiments without departing from the scope of the present application. Accordingly, the present application is not limited to a particular embodiment, but extends to various modifications that nevertheless fall within the scope of the application. It should also be understood that the phraseology and terminology employed herein is for the purpose of description only and should not be regarded as limiting.
This application claims the benefit of U.S. Provisional Application No. 62/362,695, entitled “Sensor System for a Seismograph,” and filed Jul. 15, 2016, which application is hereby incorporated by reference in its entirety.
Number | Date | Country | |
---|---|---|---|
62362695 | Jul 2016 | US |