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Changes for page ANU Seismic Data Loggers

Last modified by robert on 2025/06/27 16:42
From version 49.1
edited by robert
on 2025/06/27 16:42
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 (higher sample rates draw more power but only marginally, < 5mW). 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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165 165  
166 166  = Instrument Response =
167 167  
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.
160 +Both the TerraSAWR and LPR-200 use the same ADS1281 analog-to-digital converter chip and are designed to have identical instrument response. Depending on the output sample rate (e.g. 100 Hz, 250 Hz, 1000 Hz) amplitude response is consistently flat up to ~~100 Hz but phase response can vary above 1 Hz at 100 Hz (or 10 Hz at 250 Hz).
169 169  
170 -{{info}}
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.
172 -{{/info}}
162 +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.
173 173  
174 -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.
164 +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).
175 175  
176 -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') )
177 177  
178 178  
179 179  = ANU TerraSAWR (Gen 3, FW 3.5a, 2017- current) =
180 180  
181 -Not sure there's much left to say
171 +Words to describe the TSAWR would go here, if needed
182 182  
183 183  
184 184  
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210 210  
211 211  
212 212  
213 -
214 -
215 215  (% class="box" %)
216 216  (((
217 217  = TerraSAWR Specs =
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