Innovative Seismic Switch with 3 axis seismometer and 2 digital outputs, communicates over RS-232, RS-485 and ethernet. MiniOS7 Operating System.  Supports Operating Temperatures from -25°C ~ +75°C


Innovative Seismic Switch with 3 axis seismometer and 2 digital outputs, communicates over RS-232, RS-485 and ethernet. MiniOS7 Operating System. Supports Operating Temperatures from -25°C ~ +75°C


GST-43-M has been phased out and replaced by SAR-713. Click here for information on SAR-713.



An Innovative Seismic Switch GST-43-M is hitting the world! Earthquakes can cause severe damage, such as fires, road/bridge damages, building collapse, etc. that really threaten people’s lives. Therefore, establishing a complete earthquake warning system becomes important and urgent to prevent any further significant damage.

With advanced warning, people could take precautions against the earthquake disaster. To meet this kind of demand, ICP DAS and San Lien Technology have cooperated to develop an innovative seismic switch--- GST-43-M.

GST-43-M is an advanced seismic switch equipped with a PC/AT embedded controller inside and running Mini OS7 operation system. GST-43-M has the brilliant feature of extreme high boot-up speed in just 0.1 second and provides real-time monitoring and/or controlling functions for any emergency reactions that are needed. In addition, the built-in tri-axial MEMS accelerometers acquired vibration signal by 100Hz sampling rate and calculate the STA / LTA algorithm to achieve earthquake detection.


GST-43-M is a modern seismometer. It contains 3-axis MEMS accelerometers and a 16-bit 80 MHz CPU to process the signals and do the communication. Signals of the 3-axis accelerometers are sampled with the rate of 160 Hz. The signals are first filtered against the high-frequency noise above 20 Hz, and then used for determining the seismic events.

It can display maximum intensity according to CWB earthquake intensity standard, maximum vector, tri-axial acceleration, instant tri-axial acceleration, etc.

A special technique is applied for this unit to determine the seismic events. GST-43-M uses STA/LTA threshold levels plus a unique clamped acceleration slope method to remove high-frequency man-made seismic noises. The false alarm rate can be greatly reduced by this technique. The new trigger method is different from the traditional one by virtue of the new software processing technique. It provides the system with the real-time composite vector calculation, zero-g level self-test and compensation. It also benefits from hardware’s long data FIFO which allow the STA (Short Time Average) and LTA (Long Time Average) values to be stably processed at high-speeds. Even the weakest seismic events can be detected while preventing false triggers induced by some man-made noises.

This unit displays the magnitude of seismic intensity which is defined to have seven levels according to ground acceleration by the Central Weather Bureau in real-time. Earthquake data such as trigger time, the magnitude level, the acceleration obtained from the composite vector, and the maximum acceleration in each axis, are also available for display. The two digital outputs on this unit can be defined by users to control other devices. It can be used to notify an elevator controller to stop the elevator at nearest floor; it can be used to cut off the gas supply or electric heaters to avoid the secondary disasters while earthquakes happen.

Both the Modbus RTU and Modbus TCP protocols are provided to directly connect to a computer, a PLC or an HMI (human-machine interface). When Modbus TCP protocol is used, up to three computers or hosts are allowed to be connected simultaneously.

  • It can be directly connected to the broadcast system or a disaster prevention system.
  • It also provides the function to initiate a connection with a Server.
  • This function is similar to ADSL dial-up when using a floating IP.
  • This unit can send messages by dialing.
  • It allows people in central control room to receive immediate messages.



Two Digital Outputs are available for performing users’ control requirements. The range for triggering the DO can be set from 2 mg to the maximum measurable value. Tri-axial MEMS accelerometers provide high-precision digital acceleration values. A 16-bit CPU running at 80 MHz performs the necessary digital signal processing. Self-testing is done for automatic zero level adjustments. The STA/LTA threshold trigger algorithm is applied for seismic data recording. The composite vector acceleration value of three-axis can be obtained in real-time. This unit can record the maximum composite vector output value and its tri-axial components; it also can record the maximum accelerations for each of the three axes.

Both the Modbus RTU and Modbus TCP protocols are available for communication. The reference clock can be synchronized with those of others by the NTP function. The unit can directly connect to a PC, a PLC, or an HMI. Maximum three clients are allowed to communicate with this module at the same time through Modbus TCP protocol.


Type Tri-axial MEMS
Range ± 2 g (X Y Axes)
+ 1 g / -3 g (Z Axis)
Frequency Response 0 ~ 20 Hz
Shock 500 g/0.5 ms
3000 g/0.1 ms
Memory -
Modbus Starting Address 100
EQ File Record -
ADC Resolution 12 Bit
Digital Resolution < 0.001g
Earthquake Gauge
Algorithm STA/LTA
STA Setting Range 0.1 ~ 100 second
LTA Setting Range 0.1 ~ 100 second
Offset Period 30 ~ 32767 min
Event Duration Time 1 ~ 200 s
Switch Setpoints
Digital Output Numbers 2
Setport Range 2 ~ 1960 mg
Contact Type Open Collector
Contact Capacity 0.6 A DC
Hold-On time Same as Event
Duration Tim
CPU 80186 or compatible (16-bit and 80 MHz)
Flash 512 KB; Erase unit is one sector (64K bytes); 100,000 erase/write cycles.
Data retention: 40 years; 1,000,000 erase/write cycles.
NVRAM 31 Bytes (battery backup, data valid up to 10 years)
RTC (Real Time Clock) RTC Provide seconds, minutes, hours, date of week/month; month and year, valid from 1980 to 2079
64-bit Hardware Serial Number Yes
Built-in Watchdog Timer Yes (0.8 second)
Communication Interface
COM1 RS-232 (TxD, RxD, CTS, RTS and GND); Non-isolated
COM2 RS-485 (D2+, D2-; self-tuner ASIC inside); Non-isolated
Ethernet Port 10/100Base-TX Ethernet Controller
(Auto-negotiating, Auto_MDIX, LED indicator)
COM Port Formats
Data bit 8
Parity None
Stop bit 1
Modbus Formats
Modbus TCP 3 Host Simultaneously
Modbus ID Default 101, settable
Modbus Function Function 3 and 16
Modbus Variables Address 100 ~ 158, 171 ~ 191 include Real Time Acceleration, Event Information,
IP Address Setting,Server IP Address Setting,NTP IP Address Setting, etc
LED Display
5-Digit 7 Segment LED Display Yes
System LED Indicator Yes
Hardware Expansion
I/O expansion bus Yes
User defined I/O pins 14 pins
W x H x D 72 mm x 123 mm x 35 mm
Operating Environment
Operating Temperature -25°C ~ +75°C (-10~60)
Storage Temperature -40°C ~ +80°C (-20~70)
Relative Humidity 5 ~ 90% RH, non-condensing
Protection Power reverse polarity protection
Frame Ground for ESD Protection Yes
Required Supply Voltage +10 ~ +30 VDC (non-regulated)
Power consumption 2.5 W for GST-43/GST-43-M

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