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Changes for page ANU Seismic Data Loggers

Last modified by robert on 2025/09/16 13:22
From version 61.1
edited by robert
on 2025/08/07 16:41
Change comment: There is no comment for this version
To version 65.1
edited by robert
on 2025/09/16 13:18
Change comment: There is no comment for this version

Summary

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26 26  (% class="wikigeneratedid" %)
27 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>>doc:Instrumentation.Peripheral Equipment.WebHome]] for a more comprehensive overview of this kind of setup)
28 28  
29 += GPS Considerations =
30 +
31 +GPS is required for the data to have accurate timestamps. A standard 3-5V 1575.42 Mhz coaxial cable works fine and can be found for relatively cheap (e.g. [[https:~~/~~/www.elecbee.com/en-3555-gps-antenna-bnc-male-for-garmin-gps-120120xl125-sounder-with-cable-2m) >>https://www.elecbee.com/en-3555-gps-antenna-bnc-male-for-garmin-gps-120120xl125-sounder-with-cable-2m]]
32 +
33 +The TerraSAWR has a built-in GPS but this doesn't work as well, especially if the logger is (wisely) buried. **The LPR does NOT have a built-in GPS antenna, so an external antenna is mandatory.**
34 +
35 +In a pinch, a severed or broken antenna can be mended back together relatively easily by non-experts. Even stripping the wire and twisting it back together by hand on site is possible!
36 +
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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32 32  
33 33  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.
34 34  
35 -== The format for ANUSRSetup.txt / LPR200s will be a single line of text that looks like this: ==
43 +=== The format for ANUSRSetup.txt / LPR200s will be a single line of text that looks like this: ===
36 36  
37 37  {{{XXX195G0100010034864 2 }}}
38 38  
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52 52  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)
53 53  )))
54 54  
55 -== The format for TSAWR loggers is shorter: ==
63 +=== The format for TSAWR loggers is shorter: ===
56 56  
57 57  (% class="box errormessage" %)
58 58  (((
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71 71   and seismometer serial number (9999).
72 72  
73 73  
74 -== The formatting process using the logger: ==
82 +=== The formatting process using the logger: ===
75 75  
76 76  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
77 77  
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170 170  
171 171  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 (for better or worse!).
172 172  
181 +In the logger's menu, 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.
182 +
173 173  //(The 600+ Stage 3 SINC coefficients during the initial 1024k > 16k decimation were left off as they slowed down the process x10 and contribute at most 0.3 db amplitude and 0.31 ms phase delay discrepancies, and primarily only to frequencies near the nyquist. If for some reason you want to add this phase manually we can share the parameters with you.)//
174 174  
175 -For the most part, the data logger response essentially flat when the samplerate output is set to 100 Hz or less and for seismological purposes is likely to be impossible to detect below 20 Hz regardless.
185 +You might notice that the response information may come in two versions. The response from our website (see link below) includes the 2nd "sensor gain" stage for clarity. e.g. here is a Trillium Compact 120 & ANU Logger response
176 176  
177 -In the logger's menu, 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.
187 +##Channel Response
188 + From M/S (Velocity) to COUNTS ()
189 + Overall Sensitivity: 3.95452e+08 defined at 1.000 Hz
190 + 8 stages:
191 + Stage 1: PolesZerosResponseStage from M/S to V, gain: 754.3
192 + Stage 2: ResponseStage from V to V, gain: 0.25
193 + Stage 3: CoefficientsTypeResponseStage from V to COUNTS, gain: 2.09715e+06
194 + Stage 4: FIRResponseStage from COUNTS to COUNTS, gain: 1
195 + Stage 5: FIRResponseStage from COUNTS to COUNTS, gain: 1
196 + Stage 6: FIRResponseStage from COUNTS to COUNTS, gain: 0.99998
197 + Stage 7: FIRResponseStage from COUNTS to COUNTS, gain: 1##
178 178  
199 +
200 +However, if retrieving from AusPass or IRIS, the 2nd "sensor gain" stage is combined with the logger gain. This has no affect, but you may detect that the former Stage 2 V->V ResponseStage has been merged into the Stage 3 gain.
201 +
202 +##Channel Response
203 + From M/S (Velocity) to COUNTS ()
204 + Overall Sensitivity: 3.9546e+08 defined at 1.000 Hz
205 + 6 stages:
206 + Stage 1: PolesZerosResponseStage from M/S to V, gain: 754.3
207 + Stage 2: CoefficientsTypeResponseStage from V to COUNTS, gain: 524288
208 + Stage 3: FIRResponseStage from COUNTS to COUNTS, gain: 1
209 + Stage 4: FIRResponseStage from COUNTS to COUNTS, gain: 1
210 + Stage 5: FIRResponseStage from COUNTS to COUNTS, gain: 0.99998
211 + Stage 6: FIRResponseStage from COUNTS to COUNTS, gain: 1##
212 +
213 +
214 +For the most part, the data logger response essentially flat when the samplerate output is set to 100 Hz or less and for seismological purposes is likely to be impossible to detect below 20 Hz regardless.
215 +
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') ).
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238 238  (% class="box" %)
239 239  (((
240 240  = TerraSAWR Specs =
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292 292  )))