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Changes for page ANU Seismic Data Loggers

Last modified by robert on 2025/08/08 16:09
From version 55.1
edited by robert
on 2025/08/06 15:07
Change comment: There is no comment for this version
To version 63.1
edited by robert
on 2025/08/08 16:05
Change comment: There is no comment for this version

Summary

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104 104  
105 105  This menu also displays the firmware version, battery, external, and solar voltages, and the temperature of the system.
106 106  
107 -* Check all Initialisation Parameters are marked as successful.
108 -* Check that solar voltage is above 10 V, otherwise the station will not last long.
107 +* Check that all //Initialisation Parameters// are marked as successful.
108 +* Check that solar voltage is above 10 V in the software, or preferrably physically check that the battery's voltage is increasing via a DMM.
109 109  
110 110  == Live Seismometer Data ==
111 111  
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119 119  
120 120  This menu displays the status of the stations' GPS connection. The screen lists; UTC time, UTC date, latitude, longitude, altitude, number of satellite connections, and SNR.
121 121  
122 -* Check that the station is connected to satellites
122 +* Check that the station is connected to satellites. 3 or more should be perfectly adequate to keep time.
123 123  
124 124  == SD Information ==
125 125  
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152 152  
153 153  (% class="box errormessage" %)
154 154  (((
155 -NOTE: Ensure the 'RECORD ON RESTART' option is marked with a cross.
155 +Again, ensure the 'RECORD ON RESTART' option is marked with a cross (the default setting). This ensures that the logger will record any time it receives enough power!
156 156  )))
157 157  
158 158  (% class="wikigeneratedid" %)
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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.
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  
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}}
173 +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.
176 176  
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.
175 +//(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.)//
178 178  
177 +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
178 +
179 +##Channel Response
180 + From M/S (Velocity) to COUNTS ()
181 + Overall Sensitivity: 3.95452e+08 defined at 1.000 Hz
182 + 8 stages:
183 + Stage 1: PolesZerosResponseStage from M/S to V, gain: 754.3
184 + Stage 2: ResponseStage from V to V, gain: 0.25
185 + Stage 3: CoefficientsTypeResponseStage from V to COUNTS, gain: 2.09715e+06
186 + Stage 4: FIRResponseStage from COUNTS to COUNTS, gain: 1
187 + Stage 5: FIRResponseStage from COUNTS to COUNTS, gain: 1
188 + Stage 6: FIRResponseStage from COUNTS to COUNTS, gain: 0.99998
189 + Stage 7: FIRResponseStage from COUNTS to COUNTS, gain: 1##
190 +
191 +
192 +However, if retrieving from AusPass or IRIS, the 2nd "sensor gain" stage is combined with the logger gain. This has no affect, but will be one stage short:
193 +
194 +##Channel Response
195 + From M/S (Velocity) to COUNTS ()
196 + Overall Sensitivity: 3.9546e+08 defined at 1.000 Hz
197 + 6 stages:
198 + Stage 1: PolesZerosResponseStage from M/S to V, gain: 754.3
199 + Stage 2: CoefficientsTypeResponseStage from V to COUNTS, gain: 524288
200 + Stage 3: FIRResponseStage from COUNTS to COUNTS, gain: 1
201 + Stage 4: FIRResponseStage from COUNTS to COUNTS, gain: 1
202 + Stage 5: FIRResponseStage from COUNTS to COUNTS, gain: 0.99998
203 + Stage 6: FIRResponseStage from COUNTS to COUNTS, gain: 1##
204 +
205 +
206 +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.
207 +
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  
211 +[[Amplitude and phase response for ANU logger at 50 Hz>>image:ANU_50hz_response.png||data-xwiki-image-style-alignment="center" height="356" width="475"]]
212 +
213 +[[Amplitude and phase response for ANU logger at 100 Hz>>image:ANU_100hz_response.png||data-xwiki-image-style-alignment="center" height="355" width="473"]]
214 +
215 +[[Amplitude and phase response for ANU logger at 250 Hz>>image:ANU_250hz_response.png||data-xwiki-image-style-alignment="center" height="359" width="479"]]
216 +
217 +[[Amplitude and phase response for ANU logger at 1000 Hz>>image:ANU_1000hz_response.png||data-xwiki-image-style-alignment="center" height="367" width="489"]]
218 +
219 +
220 +[[Huddle test comparing a Trillium Compact 120 + TerraSAWR vs a Trillium Compact 120 + Nanometrics Centaur (M8.AUANU) at 100 Hz>>image:TC120_ANU_vs_CENTAUR.png||data-xwiki-image-style-alignment="center"]]
221 +
183 183  = ANU TerraSAWR (Gen 3, FW 3.5a, 2014- current) =
184 184  
185 185  Earliest known model is dated July 2014 (though first deployed in 2019) and our current flagship model. Lightweight and small.
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219 219  
220 220  
221 221  
261 +
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266 +
267 +
268 +
222 222  (% class="box" %)
223 223  (((
224 224  = TerraSAWR Specs =
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269 269  [[image:LPR battery.jpg]]
270 270  )))
271 271  )))
319 +
320 +
321 +
322 +
323 +
324 +
272 272  )))
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