IntroductionSEIS-UK's high frequency system is based around 15 SAQS data recording units as supplied by ISS International ltd. Up to six geophone or accelerometer channels can be recorded continuously or in triggered mode. SEIS-UK maintains a suite of 4.5Hz and 30HZ geophones, and also piezoelectric accelerometers, for use with these instruments. Alternatively, six Reftek 130-01 broadband data loggers are also available. The 130-01 is compact, light weight andlow power. These are capable of storing analog input from a variety of external sensors, including seismometers, accelerometers, tiltmeters and other geophysical sensors. SEIS-UK maintains GS-11D 4.5Hz geophones for use with the RefTek. To date, these instruments have been involved in projects to investigate icequakes in Antarctica, as well as progressive hydrofractures in Wyoming. Once configured the SAQS are reasonably simple to use and can be deployed with minimal user interaction using the integral LCD screen. However, the SAQS are potentially configurable in very large number of ways, which can lead to a complex, and potentially time consuming, pre-deployment set up. Below are datalogger and sensor specifications, shipping information and some useful downloadable material. Much of the information presented in this page is from ISS International ltd. |
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Specification, SAQS Datalogger
| Total number | 15 |
Digitiser |
Integral 24-bit |
Data output |
ISS proprietary format (converted into miniSEED) |
Memory |
Removable 40GB firewire (IEEE1394) hard drive |
Data download |
Disk swap |
System control |
ISSI software running on Linux with communication via RS232 port |
Power consumption |
3.3 - 12W, typically ~4W - dependent on the number and type of sensors connected and the sample rate used. |
Power supply |
12V DC |
Dimensions |
270mm x 250mm x 125mm |
Weight |
3kg |
Sampling rate |
50Hz - 24kHz |
Operating temperature |
-25°C to 40°C |
GPS |
External and internal GPS antenna |
Specification, RefTek Datalogger
| Total number | 6 |
Digitiser |
Integral 24-bit |
Data output |
Reftek Format |
Memory |
4MB battery backed SRAM, plus two removable CFII cards with 16Gb capacity.
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Data download |
Data from the removable flash can be read on any PC/Workstation using a CP-11 reader. Data can also be remotely downloaded from the 130-01 disk using FTP over LAN/WAN. |
System control |
Achieved either with a PDA (Palm OS) device running PCF software or with a PC or workstation running RTI application software set. |
Power consumption |
1-2.1W depending on the number of channels recording and the presence of communications. |
Power supply |
10-16V DC |
Dimensions |
135mm x 185mm x 353mm |
Weight |
2kg |
Sampling rate |
1000, 500, 250, 200, 125, 100, 50, 40 ,25 ,20, 5, 10, 1 sps |
Operating temperature |
Free running accuracy of 0.2ppm over 0 to -20°C and 0.1ppm between 0 to 60°C |
GPS |
External GPS antenna and internal high precision TCXO |
Specification, SM-6B 4.5 Hz Geophone (Input/Output Networks)
| Total number | 12 |
Natural frequency |
4.5 Hz |
| First spurious frequency | 140 Hz |
Damping |
0.56 ohm |
Sensitivity |
28.8 V/m/s |
Resistance |
375 Ohm |
Approximate useable bandwidth |
4.5-2000Hz (approx) |
| Dimensions | 116mm x 69mm x 83mm |
| Weight | 590g |
Specification, 30 Hz Geophone (ISSI)
| Total number | 15 |
Natural frequency |
30 Hz |
| First spurious frequency | 900Hz |
Damping |
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Sensitivity |
11 V/m/s |
Resistance |
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Approximate useable bandwidth |
30-2000Hz (approx) |
| Dimensions | |
| Weight |
Specification, 4.5 Hz GS-11D Geophone (RefTek)
| Total number | 6 |
Natural frequency |
4.5 Hz |
| First spurious frequency | |
Damping |
0.34 ± 20% |
Sensitivity |
81-2.54 V/in/sec |
Resistance |
Standard coil resistance of 380 ohms |
Approximate useable bandwidth |
4.5-1000 Hz |
| Dimensions | Height 33.5mm, Diameter 31.8mm |
| Weight | 0.111 kg |
Specification, Piezoelectric accelerometer (ISSI)
| Total number | 15 |
Natural frequency |
n/a |
| First spurious frequency | n/a |
Damping |
0.27 |
Sensitivity |
0.5 V/g |
Resistance |
900 ohm |
Approximate useable bandwidth |
0.2-2300Hz |
| Dimensions | |
| Weight |
All the high-frequency systems ship in aluminium Zarges cases containing a datalogger, a geophone, accelerometer, power regulation unit, a GPS antenna and all required cabling.
Power supply will be dependent on survey design and location. Batteries must be provided by the user, whilst solar cells (if used) may be available from SEIS-UK up to a reasonable capacity.
SEIS-UK is able to offer advice on the appropriate number of solar panels and batteries necessary for your deployment period and location.
| Instrument box dimensions | 600mm x 390mm x 400 mm |
| Instrument box volume | 0.9 cubic meters |
| Instrument box weight | 12.5kg (SAQS) |
| Instrument box weight | 10kg (RefTek) |
SAQS Huddle Test Sheet |
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SAQS - Recommended field procedures |
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SAQS Deployment and servicing sheets |
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Examples of SAQS screen shots |
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Configuring the ISS runtime system |
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Accelerometer datasheet |
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ISS sensors document |
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I/O SM6-B Geophone datasheet |
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Sensor comparison |
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| Reftek Inc. | ||