Trident Digitiser

The Trident is an industry leading digitiser, designed for use with the Taurus Portable Seismograph or Cygnus transceiver.  The Trident features 24 bit performance in a compact, robust package offering typical dynamic range of 142 dB.  The Trident Digitiser’s versatility allows for an optimal network design flexibility.  Numerous Trident digitisers can be daisy-chained to form a multi-channel system.  Such scalability makes Trident well suited to fixed, portable and structural monitoring networks.  Because the Trident Digitiser includes comprehensive seismometer control functions, it allows for seismometer mass centering, mass positioning, monitoring and calibration from a central site: eliminating the need for frequent site visits.

Since the Trident is not packaged with communications interface and timing systems, it can be deployed within the seismometer vault’s temperature stable environment for improved long period performance and superior data quality.
In addition, the Trident Digitiser supports bi-directional data communications, timing and power distribution, allowing for a simple twisted-pair NMXbus cable between the digitiser and the communications interface.  This feature eliminates the need to use long RF and GPS cables to accommodate the positioning of GPS, VSAT or RF antenna: reducing cost and increasing site configuration options.

Seismology digitizer

  • Superior performance, true 24-bit resolution with 142 db dynamic range

  • Versatile software programmable front-end gain to support a wide range of sensor types

  • Remote mass centering and calibration functions, ideal for broadband applications

  • NMXbus technology provides freedom in placing remote site components

  • Complete system response calibration using pseudo-random binary signals

  • Scalable design that allows individual 3-channel units to be configured separately and daisy-chained for multi-channel systems

      

SENSOR INPUTS

  

Channels:
Sampling:
Input Voltage Range:
Gain Selection:

EMC:

3 (6-channel configuration achieved by daisy-chaining two units)
Simultaneous
20V peak-to-peak differential (at gain=0.4)
Software selectable 0.4,1,2,4,8
Selectable sensitivity common for all 3 channels
EN55022, EN55011 FCC Part 15

PERFORMANCE

  

Shared Input Noise:
(100 sps)
Dynamic Range:

0.5 counts RMS (of 24 bits)
+/-4g, +/-2g, +/-1g, +/-0.5g, +/-0.25g (peak)
142 db typical (max. sine wave above shorted input level)

DIGITISER

  

Type:
Digital Filter:
Filter Type:

Proprietary high order sigma-delta
140 db attenuation at output Nyquist frequency
Linear Phase

DATA OUTPUT

  

Output channels:
 Output Sample Rates:
NMXbus ports:
User Serial Ports:
Serial Port Drivers:
Ethernet Port:
Storage Capacity:

1,2 or 3
10,20,40,50,100,200,500 sps
2
2
Buffered serial Command and Control
10-based-T
12 MB

COMMAND AND CONTROL

 

Calibrate:
Mass Center:
Configuration:
Software Upload:
Test Code:
Reboot:

 Initiates calibration sequence 
Initiates mass centering (STS-2 and CMG-3 series seismometers)
Get/Change/Save/Copy current configuration
Upload new DSP firmware 
Allows the user to test new code downloaded via the NMXbus
Reboots the Digitiser

POWER

  

Supply Voltage:
Power Consumption:
Protection:

9-36 V (over NMXbus)
1.8W typical, 100 sps  continuous aquisition
Reverse-voltage and over-voltage protected
Self-resetting over-current protection

ENVIRONMENT

  

Operating Temp:
Packaging:

-20°C to +55°C
Machined aluminum, IP-67 compliant

INSTRUMENT STATE-OF-HEALTH

  

Power Supply Voltage:
Temperature:
3 External Inputs:
3 Max. Signal:
3 Calibration Active:
3 Controls Active:
3 Signal Clipped:
Time Since Last Locked:
Diagnostic SOH:

DC Voltage from NMXbus
Internal Temperature
Input voltage, commonly used for mass position
Max value of signal per channel per second
Each bit indicates if calibration is active
Each bit indicates if control line toggled from default
Each bit indicates if input signal clipped
No. of seconds free running without timesaver
A number of software diagnostic and statistical counts are also included as SOH messages

TIMING SYSTEM

  

Type:
Time Accuracy:
Internal Oscillator:
GPS Receiver:
Antenna:
Antenna Cable:

UTC timed with digitally controlled VCXO clock disciplined by GPS time code receiver
<10 ms with GPS locked
1 ppm
12 Channel
External active antenna, 26 db gain
3m standard, 10m optional