RU2040019C1 - Method of testing digital seismoregistering channels - Google Patents

Abstract

FIELD: seismometry. SUBSTANCE: output signal of seismic transmitter is used as calibration signal. Two successive measurements of it are conducted with formation of levels of calibration signal across input of analog-to-digital converter differing by N times. Time of conversion of calibration signal is monitored. Operation of seismoregistering channel is judged by value of difference of output digital signals. EFFECT: enhanced efficiency of method. 1 dwg

Description

 The invention relates to seismometry and can be used in digital field stations for the primary registration of seismic information, as well as in other fields of technology.

 Known seismic stations and methods for checking the parameters of digital seismic acquisition channels.

 In these devices, there is no control of the reliability of the conversion results performed by the analog-to-digital converter (ADC). Indeed, the presence of overload during its operation or skipping the conversion cycle is not detected. In addition, in the transmission channel of the results of the conversion performed by the ADC, malfunctions of the “eternal zero” and “eternal unit” types can occur, which are also not detected in known devices. Such data arriving for processing distort the real picture of seismic events.

 It is especially important to timely receive information on failures and failures of autonomous field seismic stations operating in the periodic mode by maintenance personnel.

 The aim of the invention is to increase the reliability of the measurement results of the signals of the seismic sensors of digital seismic stations and the diagnosis of hardware failures and malfunctions.

 The goal is achieved by the fact that two sequential measurements of the signal of the seismic sensor are carried out, forming their voltage levels at the input of the ADC, differing N times, followed by comparing the results to an allowable difference, controlling the conversion time of the ADC.

 The proposed method can be illustrated by the example of a device for monitoring the results of measuring signals of seismic sensors with increased reliability, shown in the drawing.

 The device contains seismic sensors 1, a switch 2, an amplifier 3 with a variable gain, an ADC 4, a timer 5, a processing time register 6, a control and processing device 7, I8 logic elements (their number corresponds to the ADC capacity), code comparison unit 9, device 10 information output. As the device 7 control and processing can be used built-in computer with interface circuits. Blocks 1, 2, 3, 4, 7, 10 are implemented in hardware, blocks 5, 6, 8, 9 can be implemented in software.

 The device operates as follows.

 The signals from the seismic sensors 1 are fed to a switch 2, controlled from the first output of the control and processing device 7, and then through an amplifier 3 with a variable gain to the first input of the ADC 4. According to the Start signal, from the second output of the control and processing device 7 to the second input The ADC converts the voltage at the first input of the ADC into its corresponding digital code.

 Conversion of the signals of the seismic sensors is carried out in the following sequence. After connecting the next seismic sensor 1 through the switch 2 to the amplifier 3, it automatically or by command from the fourth output of the control and processing device 7) sets the gain corresponding to the nominal value of the input signal. The ADC 4 converts this signal into a digital code, which, upon command from the fifth output of the control and processing device 7, is written via AND gate 8 to the code comparison unit 9. On command from the fourth output of the control and processing unit, the gain of amplifier 3 is set to N times smaller. The next conversion of the ADC 4, but for N times smaller input signal.

 In block 9 code comparison compares the codes of the previous and current conversions. If the difference in codes does not exceed the predetermined value in advance, then the performed transformations are considered reliable and the code value stored in the code comparison unit is transmitted to the third inputs of the control and processing device 7 for further processing. Otherwise, a mismatch signal is received from the code comparison unit 9 to the fourth input of the control and processing device, the measured value is recognized as invalid and the program proceeds to the processing of this abnormality.

 As a result of two consecutive conversions with their comparison, failures that can occur during the analog-to-digital conversion are rejected.

 Performing sequential transformations of different voltage levels leads to a change in the binary codes of the conversion results. This allows you to diagnose failures of individual bits of the ADC, as well as the information path from it to the control and processing device (computer).

 The value of the coefficient n can be chosen a multiple of two to the power of k. Moreover, to scale the codes of the first and second measurements, before comparison, it is sufficient to shift the second measurement code by k bits to the left.

 The allowable code difference when comparing two measurements is determined by the error of the controlled amplifier and ADC, the dynamic characteristics of the measured signal, the noise level, and possibly other factors.

 Using a calibrated voltage to test the performance of the ADC may not provide the ability to diagnose failure of individual discharges, since this voltage assumes the stability of the codes of the conversion results.

 The “Start” signal simultaneously arrives at the first input of timer 5 and starts it to work out the time interval, the duration of which is set by the register 6 of the run time from the third output of the control and processing device 7. This time should exceed the time that the input voltage is converted to a digital code by the ADC, but should be less than the period of its operation.

 When the ADC 4 is activated, at the end of the conversion, a ready signal is generated at its first output, which arrives at the first input of the control and processing device 7. This signal is fed to the second input of timer 5, stopping its operation.

 If, for any reason, the ADC does not start (for example, due to its malfunction), then timer 5, at the end of the specified time interval, provides a normal signal to the second input of the control and processing device, by which the processing program for this standard starts to run.

 In this way, the ADC malfunctions are diagnosed, and zero results are excluded for further processing, as well as the possible looping of the measurement program while waiting for a ready signal from it.

 The ADC 4 overload control at the input is carried out by generating an overload signal and supplying it to the fifth input of the control and processing device, which leads to the start of the processing program for this abnormality. This method can be implemented if the ADC has “Overload” and “Ready” signals.

 As a result of the introduction of measures to increase the reliability of the measurement data carried out during the measurement process, only “normal” measurements are processed, and in the output of the results of processing the measured signals of the seismic sensors, abnormal signs can form, which are transmitted further to the central processing station of the seismic information, and (or) displayed on the appropriate display for fixing it by maintenance personnel and making decisions on further operation of the station.

 Similarly, reliability can be exceeded in digital measurements of other quantities, such as frequency.

Claims (1)

 METHOD FOR MONITORING DIGITAL SEISMIC RECORDING CHANNELS, including supplying an analog calibration signal to the channel input and analyzing the output digital signal, characterized in that, in order to increase the reliability of measurements, the output signal of the seismic sensor is used as a calibration signal, two consecutive measurements are carried out, forming levels the calibration signal at the input of the analog-to-digital converter, differing N times, control the conversion time of the calibration signal, and by the value of Nost digital output signals are judged on the work seysmoregistriruyuschego channel.

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