Skip to Content

Changes for page ANU Seismic Data Loggers

Last modified by robert on 2025/08/08 16:09
From version 48.1
edited by robert
on 2025/06/20 12:31
Change comment: There is no comment for this version
To version 56.1
edited by robert
on 2025/08/06 16:45
Change comment: There is no comment for this version

Summary

Details

Page properties
Content
... ... @@ -14,9 +14,9 @@
14 14  
15 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.
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.
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, < 5 mW). 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.
19 +For very sunny environments (latitudes < 30) a 20 Volts 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 20  
21 21  (% class="box infomessage" %)
22 22  (((
... ... @@ -23,6 +23,9 @@
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>>doc:Instrumentation.Peripheral Equipment.WebHome]] for a more comprehensive overview of this kind of setup)
28 +
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.
... ... @@ -86,7 +86,7 @@
86 86  
87 87  * XX.ANUSR network and station name
88 88  * 100 Hz Sample Rate
89 -* 40V pp (or +/- 20 V) gain / Trillium Compact seismometer version
92 +* 40 Vpp (or +/- 20 V) gain / Trillium Compact seismometer version
90 90  * Record on Restart enabled
91 91  
92 92  Note that if a user sets the gain incorrectly, this can be fixed later (assuming nothing clipped) by multiplying or dividing by factors of 2. The gain setting can be looked up from the logfile, else you may have to guess from a PSD or other method.
... ... @@ -134,7 +134,7 @@
134 134  
135 135  The seismometer model and serial number (up to 10 characters) can be set. Seismometer model options include:
136 136  
137 -* Trillium Compact (same for 20 and 120)
140 +* Trillium Compact (same for 20s and 120s models)
138 138  * CMG - 3ESP
139 139  * Guralp 40T
140 140  * LE-3D Lite
... ... @@ -165,32 +165,38 @@
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. 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).
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.
169 169  
170 -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 +{{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
175 +{{/info}}
171 171  
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).
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.
173 173  
174 174  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') ).
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!
182 +[[Amplitude and phase response for ANU logger at 50 Hz>>image:ANU_50hz_response.png]]
179 179  
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"]]
184 +[[Amplitude and phase response for ANU logger at 100 Hz>>image:ANU_100hz_response.png]]
181 181  
182 182  
183 -= ANU TerraSAWR (Gen 3, FW 3.5a, 2017- current) =
187 +[[Amplitude and phase response for ANU logger at 250 Hz>>image:ANU_250hz_response.png]]
184 184  
185 -Not sure there's much left to say
186 186  
190 +[[Amplitude and phase response for ANU logger at 1000 Hz>>image:ANU_1000hz_response.png]]
187 187  
188 188  
189 -= ANU LPR-200 (Gen 2, FW 2.6a/2.7a, 2013 - current) =
193 +[[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"]]
190 190  
191 -Ditto the mighty LPR!
195 += ANU TerraSAWR (Gen 3, FW 3.5a, 2014- current) =
192 192  
197 +Earliest known model is dated July 2014 (though first deployed in 2019) and our current flagship model. Lightweight and small.
193 193  
199 += ANU LPR-200 (Gen 2, FW 2.6a/2.7a, 2011 - current) =
200 +
201 +Earliest known model is dated May 2011 (but first deployed November 2012) and still in use today. Potentially capable of housing much larger batteries than the TSAWR due to the larger cavity space.
202 +
194 194  = ANU "ANUSR" (Gen 1, 2003? - 2012) =
195 195  
196 196  This logger has been retired for a long time and has a different instrument response. It used modular component boards and was powered via an acrylic case of 6 x 6V lantern batteries. There is a somewhat complete one above the CAT lab door if anyone is so inclined to have a look.
... ... @@ -215,6 +215,14 @@
215 215  
216 216  
217 217  
227 +
228 +
229 +
230 +
231 +
232 +
233 +
234 +
218 218  (% class="box" %)
219 219  (((
220 220  = TerraSAWR Specs =
ANU_1000hz_response.png
Author
... ... @@ -1,0 +1,1 @@
1 +XWiki.robert
Size
... ... @@ -1,0 +1,1 @@
1 +22.7 KB
Content
ANU_100hz_response.png
Author
... ... @@ -1,0 +1,1 @@
1 +XWiki.robert
Size
... ... @@ -1,0 +1,1 @@
1 +21.3 KB
Content
ANU_250hz_response.png
Author
... ... @@ -1,0 +1,1 @@
1 +XWiki.robert
Size
... ... @@ -1,0 +1,1 @@
1 +22.9 KB
Content
ANU_50hz_response.png
Author
... ... @@ -1,0 +1,1 @@
1 +XWiki.robert
Size
... ... @@ -1,0 +1,1 @@
1 +21.3 KB
Content
TC120_ANU_vs_CENTAUR.png
Author
... ... @@ -1,0 +1,1 @@
1 +XWiki.robert
Size
... ... @@ -1,0 +1,1 @@
1 +63.9 KB
Content