TDE series Seismic Data Acquisition Systems(TDE-224C/324C/324F/324CQ/324CI)

　　TDE series seismic data acquisition systems (TDE-224C/324C/324F/324CQ/324CI types) convert the analog signals that the seismograph output into the digital signals, and output the signals with the serial ports. These systems adopt design patterns of high integration, feature wider range of dynamic response, lower power consumption and the stable reliability. The systems also provide the calibrated signals including step signals, sine waves, pseudo-random signals, simulated seismic signals for the seismometer. TDE series systems have the monitoring channel that is used to monitor environmental conditions, including environmental parameters such as supply voltage, voltage of the storage battery, and temperatures.

　　These systems can connect with many kinds of seismometers such as DS－1, DS-4A, JC－V100, FBS－3A, S－13, BB－13, JD－1 and etc..

Photos | TDE-224C/324C/324F/324CQ | TDE-324CI | Technical Indicators

　　TDE-224C/324C/324F/324CQ Design Scheme as a Whole

　　Having referred to the scheme of National Seismic Bureau's crucial project "The Constuction of China Digital Seismic Inspection System" and the schemes of some similar productions, and investigated broadly the specifictions of electronic components, we determined the following design scheme: highly integrated design mode, GPS digital clock synchronization technology, modularized design technology and low power consumption.

　　1. highly integrated design mode

　　In order to ensure the advantage and reliability of the whole performance of the digital seismic data acuqisition system, we choosed the highly integrated design mode. In detail, we selected highly integrated, low power consumption components, reduced farthest the number of components, and improved the general technical specifications. In fact, such a design mode can reduce the noise and intermodular crosstalk greatly. This design mode also simplified the design, installing, debugging and maintenance procedures.

　　2. GPS digital clock synchronization technology

　　In digital seismic data acqusition system, the time standard of digital data is very important, especially the data were gathered from different network stations. The absolute time error should be less than 1ms. In the early 1980's, the department of defense of the United States developed the Global Position System, its time accuracy is less than 1us. GPS has been widely used in military and civil affairs, its time accuracy can satisfy the demand of the seismic data acqusition system, so we use GPS as the time reference of TDE.

　　3. modularized design technology

　　we used a multi-CPU parallel computation design mode. Each modular control, process data independently and parallelly. We used Intel 96 series 16-bits singlechip as main processor to monitor every sub-modulars' statuses, and perform the data collection, processing and transmitting functions.

　　4. low power consumption

　　Most of the newly built seismic stations are unmanned, and no AC power supply but solar energy and other power supplys which has limited capacities, so the power cnsumption should be reduced as much as possible. We achieved such goal through components selecting and circuit designing.

　　Principle Chart and functions

　　1. It can be connected with a three-component seismometer, and perform a three-component observation.


　　2. TDE used the oversampling technology. Sample-rate of A/D Convertor is 18kHz. Three channels sample parallelly. Filtered by FIR or IIR digital filters, sampled data are converted into 100Hz or 50 Hz digital signals. The corresponding passband is 0-20Hz. TDE provided two kinds of digital filters: linear phase and minimum phase respectively.


　　3. TDE can be connected with seismometers of different sensitivities because of the program controlled amplifier. So it is adaptive to different noise level of the stations and can achieve the maximum dynamic range. User can set the amplifier gain according to the noise level of the stations and the output sensitivites of seismometers. TDE provided 7 grades of gains:1, 2, 4, 8, 16, 32, 64. Gains of different channels can be set dividually.


　　4. TDE has a inner GPS receiver, which provide highly precise timing signal to ensure microsecond time precision. At the same time, user can get the station's position information from GPS data.


　　5. We used 12-bits D/A convertor as the calibrating signal generator, which can provide square, sine and pseudo-random signals. Parameters of the calibrating signals such as impulse width, frequency, amplitude, and daily calibrating times can be set by software.


　　6. Zero compensation of TDE is implemented by digital filter directly. When this function is enabled, TDE can detect the zero of itself and the seismometer connected, and remove it. Because the time constant of the DC filter is very large, it make no effect to the low frequency response of TDE.


　　7 TDE can use both of the COM to transfer data and control. COM1 is connected to the communication device to perform real time data transfer. It works in simplex mode. COM2 is used for parameter setting. User can connect it with a notebook computer, then transfer corresponding parameters to TDE. COM1 is still working when COM2 is in use.


　　8. All the calibrating parameters of TDE are saved in flash memory, so none of them will lose if an unwanted power-off occurs. Parameters can be read from flash memory when the system resets.


　　9.In order to increase the reliability, TDE uses airproof container, without any keys and switchs outside. All the parameters are set by software through COM2.


　　10.In some unusual situation, TDE can change its output data format, which is transfered by COM1. So TDE can also be used in systems other than TDS and Adapt and can be used as OEM production or the substitution of other similar productions.


　　TDE-224C seismic data acquisition system has passed the test by the CEPREI（China Electronic Product Reliability and Environmental Testing Research Institute）in July 1998.

　　TDE-324C/F/CQ seismic data acquisition systems are designed according to the technical specifications of the Ninth Five-year Program. They have passed the test by the CEPREI in July 2000, the test report NO. is YW00372.

TDE-324CI:

　　TDE-324CI seismic data acquisition recorder is designed in compliance with the technical specifications of the Tenth Five-year Program worked out by the China Earthquake Administration, and by considering feedback information from domestic users, drawing lessons and assimilating experience. It is my company new generation seismic data acquisition recorder of independent development. It follows the latest international trends in electronics design. The newly released state-of-the-art CS537x series 24 bits AD chip, some high performance and low power consumption RISC processor/DSP devices are used.It is also installed with a high reliable real time operating system (RTOS) that is FAA Safety Certified, which is widely used in airplane and spacecraft.

　　TDE-324CI seismic data acquisition recorder has the following features:

　　1. The adopted CS537x series 24 bits AD devices are enhanced and upgraded products of the CS532x series widely used in seismic industry during the implementation of the Ninth Five-Year Program. Featuring wider range of dynamic response, lower power consumption, smaller total harmonic distortion (THD), and adjustable, full-scale, programmable 7-level controlled input signals, these devices assures high performance of the system.

　　2. Design patterns of high integration and low power consumption are used. The system is integrated with three channels, 24-bit seismic data acquisition, high-volume of electronic hard drive (CF Card) data storage, station status monitoring, multiple signal calibration, button setting, display of digital tube parameters, and system lightning protection. Power consumption when GPS is idle is less than 0.9W.

　　3. TDE-324CI System enables D/A calibration output based on the set time or by corresponding command. Enables calibration-enabled function and GPS control switch. The calibrated output signals include step signals, sine waves, pseudo-random signal encoding, simulated seismic signal output, and so on.

　　4. The monitoring channel is used to monitor environmental conditions, including environmental parameters such as supply voltage, voltage of the storage battery, and temperatures. The monitoring data flow of the seismic station may be transferred to the Station Network Center along with the real time data flow without taking up other data channels, or interrupting other real time data flow to transfer monitoring parameters. A data processing software seperats real time quake data from the monitoring parameters, which are recorded, saved and processed around-the-clock.

　　5. TDE-324CI System with standard configuration uses a pluggable electronic disc (CF card) to keep semistic data. The CF card has a volume up to 4G. The current equipment with standard configuration provides storage of 512M. A revised SEED-STEIM2 compressed data format is used for data storage, whose data compression rate is high.

　　6. Supports TCP/IP protocol. Supports realtime multicast communication based on Internet/VPN netweork protocols; supports RMON services, breakpoint data retransmission, etc. Supports DDN data transmission and wireless/GPRS/CDMA data transmission, supports multiple transmission mode for data networking and shareing on the same platform (including serial port/network); support data request and exchange among multiple Seismograph Networks. Since the data transmission via network is faster than serial port data transmission, the system ensures data transimission on Internet of continuality and reliability, meeting the requirement of seismograph network for realtime transmission and regional remote measurement.

　　7. The system is configured with a watchdog and implemented with hardware. When the system fails, it can be reset automatically. The system is programmed online, i.e. an acquisition/control system utility may be upgraded with a notebook computer through a RS-232 serial port.

　　8. Display panel with buttons, LED light and digital display on it provides visual display of parameters status, Optionally results from button setting can display directly on the panel, so that basic operational status might be viewed when no computer is available.

Technical Indicators:

TDE-324CI seismic data acquisition recorder Technical Indicators
Data acquisition channel	3 channels (6 channels, optional)
Sensor interface	compatible with DB/T13-2000 rules
Signal input mode	Double-ended differential signal input
A/D conversion	24 bit
Input impedance	single-ended 160KΩ，double-ended 320KΩ
Input signal scale value	7-level progam-contrlled optional gains of 1，2，4，8，16，32 and 64, (corresponding to ±0.3125V, ±0.625V, ±1.25V, ±2.5V, ±5V, ±10V, ±20V differential signal input)
Dynamic Range	≥135dB @50sps/chn，≥133dB @100sps/chn，≥131dB @200sps/chn
System noise	< 1 LSB（effecitve value）
Nonlinear distortion	< -110dB @ 50sps/chn
Interchannel crosstalk	< -110dB
Digital filtering	FIR digital filter, optional linear phase shift and minimum phase shift
Passband ripple	< 0.1 dB
Ouside passband attenuation	> 135 dB
Output sampling rate	1、5、10、20、25、40、50、100、125、200、250、333、500Hz
Band range	0～0.4、2、4、8、10、16、20、40、50、80、100、133、200Hz
De-zeroing filter	one-step digital high-pass filter
High-pass filtering	Cutoff cycle 225s,450s,900s,1800s,3600s,7200s or close the filter
Calibration signal generator	16-bit DAC, program-controlled wave form output, calibration output current and voltage output are optional. When calibration current, the full range is ±5mA. When outputting voltage calibration, the full range is ±5V
Number of calibration signal channels	3-channel, Calibration enabled output control. When calibration is disabled, calibration output and external circuit are entirely physically isolated
Calibration signal type	Step, sine wave, pseudo random coding signal, simulated seismic signal
Calibration output	Signal frequency, amplitude, cycles are set and controlled by utility
Calibration Enable Mode	Instruction and timing modes
Frequency stability	Temperature compensation voltage controlled crystal oscillator(TCVCXO), real time frequency accuracy monitoring
Time check mode	Built-in GPS receiver, GPS second pulse adjustment of crystal oscillator frequency TCVCXO through phase locked loop (PLL) voltage control
Time service/on time precision	Superior to 1ms
GPS Operating Mode	Continuous or time switch time correcting
Environment and Status Monitoring	6-way standalone A/D monitoring channels for a collector, automatically monitoring the status of the environment and the seismometer, monitoring the zero drift of the seismometer (MASS POSITION), service voltage of the stations and the observatories, voltage of accumulator, monitoring temperature parameters of the stations and the observatories
Recording function	Support internal continuous/triggering record wave form, volume extendable, support over 10-day consecutive data storage (3 tracks/s 100 points sampling)
Record format	Corrected SEED-Steim2 compression mode
Recording medium	Pluggable CF card electronic disc, 512MB for standard configuration, optional HDD (under the optional HDD condition, the range of system operating temperature and system power consumption indicators may drop)
Communication interface	Standard RS-232C series port, standard RJ45/LAN Ethernet interface
Monitoring setting	Display collected parameters through keys on panel and LED nixie tubes
Communication protocols	Support TCP/IP protocol, support real-time, multicast data transmission over Internet/VPN network, support remote management, and support data retransmission at breaking point, etc. Support DDN, wireless/GPRS/CDMA data transmission. Support data networking and sharing among multiple data transmission (including serial port/network etc.) on the same platforms, support data call and switching among multiple seismograph network and centers.
Information transferred	Real-time waveform, monitoring data, parameter/message, local recording data
Management Software	Functions, such as parameter setting, self-checking function, real-time graphic display and save, may run on a notebook PC with online help.
Lightning protection	Set at all end of the power, RS232 signal, network signal, and seismometer signal.
Supply voltage	DC 12V (normally work under 6～18V)
Power consumption	<1.5W(GPS off，system run on normally)
Operating temperature	-20～65℃
Self Enable Function	Self check, reset when the machine is down (including reset for no output signals), self rebooting functions
Dimensions of the device	335×180×44 mm
Weight	3 kg
Installation type	Fit in 19”industrial standard cabinet
Packing and transportation	Accord with GB/T 6587 Rules to 3-level exact instrument

　　Want to know more about them, please download separately "TDE-224C/324C/324F/324CQ/324CI Digital Seismic Data Acquisition System Manual".

　　Correlative Links： ADAPT Regional Digital Telemetry Seismic Network System,　　TDS Single Digital Seismic Data Processing System,　　Seismic Data IP Transmission & Staroge Unit (ITU).

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