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Changes for page ANU Seismic Data Loggers

Last modified by robert on 2025/08/08 16:09
From version 53.1
edited by Jack Dent
on 2025/07/22 13:13
Change comment: There is no comment for this version
To version 49.1
edited by robert
on 2025/06/27 16:42
Change comment: There is no comment for this version

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1 +XWiki.robert
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23 23  Power issues are easy and cheap to solve relative to the cost of your experiment, don't skimp!
24 24  )))
25 25  
26 -(% class="wikigeneratedid" %)
27 -In the case of an LPR, there is a large compartment for housing an internal battery, able to accommodate anything from a 10-30Ah battery. To use a standard lead acid battery with a positive and negative terminal, a 6 pin adaptor must be used. This ensures the voltage from the external power port (pins A and C) connect to the battery and ensure the system actually recharges. (See Peripheral Equipment for a more comprehensive overview of this kind of setup)
28 -
29 29  = Data Card Formatting and Information =
30 30  
31 31  Both the TerraSAWR and LPR-200 require SD Cards to be formatted in FAT32 filesystem. For 64Gb cards it can be difficult to format in FAT32, but [[software >>http://auspass.edu.au/field/fat32cardformatter.exe]]is available. ANU recommend SanDisk Extreme 150 mb/s cards in either 32 or 64Gb size. We strongly discourage using cards larger than 64Gb, and in general smaller cards are less likely to fail. We have also found that "adapter" cards (e.g. SD to microSD) are prone to having write issues and **strongly** advise against them.
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168 168  
169 169  = Instrument Response =
170 170  
171 -Both the TerraSAWR and LPR-200 use the same ADS1281 analog-to-digital converter chip and are designed to have identical instrument response. The ADC (analog to digital) chip in both loggers originally samples at 1024000 Hz and downsamples towards the output data rate via a 5th order SINC filter, then another four FIR filters. If the output is below 250 Hz, a final "pure" /5 decimation is done without any sort of FIR filter.
168 +Both the TerraSAWR and LPR-200 use the same ADS1281 analog-to-digital converter chip and are designed to have identical instrument response. The ADC (analog to digital) chip in both loggers originally samples at 1024000 Hz and downsamples towards the output data rate via various stages. First via a 5th order SINC filter, then another 32x via 3-4 2x or 4x FIR filters. If the output is below 250 Hz, a final "pure" /5 decimation is done without any sort of FIR filter.
172 172  
173 173  {{info}}
174 -The Stage 3 SINC coefficients (600+) during the initial 1024k > 16k decimation were left off as they slowed down the process x10 and contribute very little (< 0.3 db, < 0.31 ms) to the end result
171 +All SINC and FIR filters are performed internally within the logger and all phase delays are accounted for. Thus, the FIR coefficients and delays are not needed/given in the response information.
175 175  {{/info}}
176 176  
177 177  The user can choose to apply a 2nd stage "sensor gain" by selecting an instrument type in the setup menu. This effectively selects a 10 Vpp (e.g. short period sensors), 20 Vpp, 40 Vpp (most broadband sensors) regime to match the sensor's sensitivity. This has the effect of doubling amplitude from 10v to 20v, or quadrupling from 10v to 40v. If you have set your sensor correctly (and the signal isn't clipped!) you can "correct" this by simply multiplying your data by 0.5 etc. This gain manifests itself in stage 2 in the response information.
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178 178  
179 179  Instrument response can be downloaded from IRIS [[Nominal Response Library>>https://ds.iris.edu/ds/nrl/]] if need be, or [[directly from us>>http://auspass.edu.au/data/logger_response]] , or by downloading the response of an equivalent sensor at AusPass (e.g. get_stations(level='response') ).
180 180  
181 -[[Huddle test comparing a Trillium Compact 120 + TerraSAWR vs a Trillium Compact 120 + Nanometrics Centaur (M8.AUANU)>>image:TC120_ANU_vs_CENTAUR.png||data-xwiki-image-style-alignment="center"]]
182 182  
183 183  = ANU TerraSAWR (Gen 3, FW 3.5a, 2017- current) =
184 184  
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223 223  (% class="box" %)
224 224  (((
225 225  = TerraSAWR Specs =
TC120_ANU_vs_CENTAUR.png
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