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Changes for page ANU Seismic Data Loggers

Last modified by robert on 2025/06/27 16:42
From version 48.1
edited by robert
on 2025/06/20 12:31
Change comment: There is no comment for this version
To version 46.2
edited by robert
on 2025/06/15 13:57
Change comment: There is no comment for this version

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12 12  
13 13  = Power Considerations =
14 14  
15 -Both the LPR-200 (or "Low Power Recorder" 200) and TerraSAWR are designed to use as little power as possible, and more or less use the same amount of power.
15 +Both the LPR-200 (or "Low Power Recorder" 200) and TerraSAWR are designed to use as little power as possible. For very sunny environments (latitudes < 30) a 10 Watt solar panel should suffice, however there is no harm in using 20 or even a 40 Watt panel. We generally recommend 20 Watt panels with at least a 7 Ah battery.
16 16  
17 -At 100 Hz and with a GPS cable connected these loggers draw about 220 mW of power once the screen is off. Adding a sensor (e.g. a Trillium Compact 120) increases this to approximately 400 mW, or 0.4 volt-amps. So, in theory 7 Ah battery should last about 10 days without a solar panel, but in practice it seems to be a bit closer to 8 which may be due to variability in power drain while in getting GPS locks.
18 18  
19 -For very sunny environments (latitudes < 30) a 20V 10 Watt solar panel should have no issue keeping these loggers alive over the summer months, and assuming unobstructed skies should also be fine over winter. However there is no harm in using 20 or even a 40 Watt panel, especially for high latitudes, coastal regions, or areas without a full sky view. In theory up to a 60 Watt solar panel is fine, but we don't recommend anything over 40 Watts and that amount of power is already overkill.
20 -
21 -(% class="box infomessage" %)
22 -(((
23 -Power issues are easy and cheap to solve relative to the cost of your experiment, don't skimp!
24 -)))
25 -
26 26  = Data Card Formatting and Information =
27 27  
28 28  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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29 29  
30 30  The loggers can be "pre-programmed" with information (e.g. site name, sampling rate, etc) or they can be programmed in the field using the buttons on the logger. To pre-program the cards you simply edit a text file (named "[[ANUSRSetup.txt>>http://auspass.edu.au/field/ANUSRSetup.txt]]" for the LPRs, or "[[tSAWRSetup.txt>>http://auspass.edu.au/field/tSAWRSetup.txt]]" for the TerraSAWRs) and place it in the root directory on the SDCard. When the logger boots up, it will parse and load this information.
31 31  
32 -== The format for ANUSRSetup.txt / LPR200s will be a single line of text that looks like this: ==
24 +=== The format for ANUSRSetup.txt / LPR200s will be a single line of text that looks like this: ===
33 33  
34 34  {{{XXX195G0100010034864 2 }}}
35 35  
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49 49  NOTE: the 2 at the very end is for "RECORD ON RESTART". The record on restart option ensures that if the logger dies and is powered back up whilst in the field (due to battery charging cycles or other causes) that the recording will resume. (# of blank spaces before this doesn't matter)
50 50  )))
51 51  
52 -== The format for TSAWR loggers is shorter: ==
44 +=== The format for TSAWR loggers is shorter: ===
53 53  
54 54  (% class="box errormessage" %)
55 55  (((
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68 68   and seismometer serial number (9999).
69 69  
70 70  
71 -== The formatting process using the logger: ==
63 +=== The formatting process using the logger: ===
72 72  
73 73  The process for formatting an SD card within the logger is straightforward. Navigate to the "SD INFORMATION" screen and press ERASE SD CARD. This process may take up to a minute. This will result in erasing all files from the card. Upon starting recording, a new 'seed' will be written containing all the information that the logger has been set with FINISH THIS SECTION
74 74  
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171 171  
172 172  Another important thing to note is that the group delay associated with late stage FIR filters is **automatically applied in the logger**, hence there is no need to apply this in the response. These tend to max out at 0.124 seconds for most output sampling rates (0.062 s for 100 Hz).
173 173  
174 -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') ).
166 +Instrument response can be downloaded from IRIS-NRL (v2) **TODO ADD LINK** if need be, or by downloading the response of an equivalent sensor at AusPass (e.g. get_stations(level='response') )
175 175  
176 -The response info from IRIS-NRL is the "full" version which (in theory!) perfectly describes the data logger's bias on the data. However this is in many way overkill and at the cost of 1) increased metadata size and, more importantly, 2) increased CPU demand in the response removal process. Testing has shown that for signals below 100 Hz, the "full" response offers little to no benefit and can increase the time it takes to remove the response for a 1 hour window of 100Hz data by a factor of x20 or more. For earthquake arrival data this is often negligible, but for data intensive tasks like ambient noise cross-correlations this can be a severe hindrance. Thus we have created a parallel version of this response which removes the SINC and FIR filters completely. These are labelled "fast" in our [[local response archive>>http://auspass.edu.au/data/logger_response]] and essentially truncate response stages 3 onwards into a "fake" decimation step from 1024000 Hz to the desired output samplerate with no filtering whatsoever.
177 177  
178 -In the below we show both responses applied to a test signal with a frequency range of 1000 seconds to 100 Hz. The maximum discrepancy in signal is less than 0.01% (1.0001) which is far below what you should expect from the mechanical inconsistencies intrinsic to the sensor itself. Thus, we strongly advise users employ the "fast" version of this response information and it is what we use for our networks by default. If you are recording at 1000 Hz, or care deeply about signals above 100 Hz (so recorded at 250 or 1000 Hz), please use the full response. Any questions, please ask!
179 -
180 -[[Testing the "full" and "fast" versions of the ANU data logger response on synthetic 250 Hz data from 1000 seconds to 100 hertz. For all intents and purposes, they are identical.>>image:full_vs_fast.png||data-xwiki-image-style-alignment="center"]]
181 -
182 -
183 183  = ANU TerraSAWR (Gen 3, FW 3.5a, 2017- current) =
184 184  
185 -Not sure there's much left to say
171 +Words to describe the TSAWR would go here, if needed
186 186  
187 187  
188 188  
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214 214  
215 215  
216 216  
217 -
218 218  (% class="box" %)
219 219  (((
220 220  = TerraSAWR Specs =
full_vs_fast.png
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