The SAR-713 is a modern seismometer equipped with three-axis MEMS accelerometers and a 16-bit, 80 MHz CPU for signal processing and communication. The signals from the three-axis accelerometers are sampled at a rate of 160 Hz. These signals are first filtered to remove high-frequency noise above 20 Hz and then used to determine seismic events.
A specialized detection technique is implemented in this unit to identify seismic activity accurately. The SAR-713 uses STA/LTA threshold levels combined with a unique clamped acceleration slope method to eliminate high-frequency, man-made seismic noise. This approach significantly reduces the false alarm rate. Unlike traditional trigger methods, this advanced software-based processing technique provides real-time composite vector calculation, zero-g level self-testing and compensation, and benefits from a long hardware FIFO buffer. The FIFO allows both the Short-Term Average (STA) and Long-Term Average (LTA) values to be processed quickly and stably. As a result, even the weakest seismic events can be detected while effectively preventing false triggers caused by artificial vibrations.
The SAR-713 displays real-time seismic intensity levels, defined across seven levels of ground acceleration according to the standards of the Central Weather Bureau. Earthquake data such as trigger time, magnitude level, composite vector acceleration, and maximum acceleration along each axis are all available for display.
Two digital outputs (DOs) can be user-configured to control external devices. For example, they can signal an elevator controller to stop the elevator at the nearest floor or disconnect gas lines or electric heaters to prevent secondary hazards during an earthquake.
Both Modbus RTU and Modbus TCP communication protocols are supported, allowing direct connection to a computer, PLC, or HMI (Human-Machine Interface). When using Modbus TCP, up to three clients can connect simultaneously. The unit can also connect directly to a broadcast or disaster prevention system and includes functionality to initiate a server connection, similar to an ADSL dial-up when using a floating IP. In this mode, the SAR-713 can automatically send event messages, allowing personnel in a central control room to receive immediate alerts.
-Two Digital Outputs (DOs) are available for user-defined control applications. The trigger threshold for each DO can be set anywhere between 2 mg and the maximum measurable acceleration.
-Tri-axial MEMS accelerometers provide high-precision digital acceleration data. A 16-bit CPU running at 80 MHz performs advanced digital signal processing for reliable operation.
-Automatic self-testing ensures accurate zero-level adjustments without manual calibration.
-The STA/LTA threshold trigger algorithm is applied for seismic data recording. The real-time composite vector acceleration of the three axes can be obtained continuously. The unit records the maximum composite vector value and its corresponding tri-axial components, as well as the maximum acceleration for each individual axis.
-Supports both Modbus RTU and Modbus TCP protocols for communication. The internal reference clock can be synchronized with other devices using the NTP (Network Time Protocol) function.
-Can connect directly to a PC, PLC, or HMI, with support for up to three simultaneous clients over Modbus TCP.
