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neilh20 posted a new activity comment 7 years, 9 months ago
Hi Jeremy
My reference to 16 was that for a total change of 0.006mm its going to be broken down to a scale, and if you choose 1/16 (as its digital) then for 0.006mm/16 you would have a target of 0.000375 mm – which is very small.
Now looking at the LP-10F spec – which with a total travel of 10mm is better than 20mm for measuring something very s…[Read more] -
neilh20 posted a new activity comment 7 years, 9 months ago
I think you have to look at all the noise sources with the level of measreument that you are looking at. So broadly for a 0.006mm range, you want some resolution in it, which defines what exactly is your 0. That in turn will translate to the noise floor that you need to exceed. So so you could use a scale of 16 – then you need to be able to…[Read more]
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Neil this has been such a great conversation. Thank you.
I don’t understand the scale of 16. Could you elaborate or point me to a reference. I’m having a hard time googling that one. This sensor is a “cheaper” version of one that is in the field being used exactly for this purpose. That sensor has a temp. coefficient of +-400 ppm/K. This seems to…[Read more]
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neilh20 posted a new activity comment 7 years, 9 months ago
Hey Jeremy,
Interesting project there – I’ve wondered about the effect on the trees when they are really transpiring in a heat wave,
and also what the delay was between heat peak for transpiration, and pulling the water from the ground, and stream.
So looking to measure 6microns, or 0.006mm across the LP-10F travel of 10.0 mm
I’m guess maybe you…[Read more]-
Those are some great questions. Tree water/soil/atmospheric relations is where a lot of this work is pointed. Some species, like the Picea abies, can swell up to 0.006 mm in a 24 hour period, others less so, so I’m looking to detect changes within the 0.000-0.006mm range.
Generally speaking, would one start with identifying noise at the power…[Read more]
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I think you have to look at all the noise sources with the level of measreument that you are looking at. So broadly for a 0.006mm range, you want some resolution in it, which defines what exactly is your 0. That in turn will translate to the noise floor that you need to exceed. So so you could use a scale of 16 – then you need to be able to…[Read more]
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Neil this has been such a great conversation. Thank you.
I don’t understand the scale of 16. Could you elaborate or point me to a reference. I’m having a hard time googling that one. This sensor is a “cheaper” version of one that is in the field being used exactly for this purpose. That sensor has a temp. coefficient of +-400 ppm/K. This seems to…[Read more]
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neilh20 posted a new activity comment 7 years, 9 months ago
Hey thanks for posting. Interesting issue.
Noise in circuits is well studied and a deeeeeep issue. In circuits there are two types of noise to manage, faster than 1hz and then probably your main concern and more challenging less that 1Hz . Filtering out noise is useful at higher frequencies where low frequency noise is not an issue.
Managing…[Read more]-
Wow some great info. Thank you very much and I will check out the your blog as it seems this career path will be heavily involved in these kinds of problems. The design is straight forward, a Li-Polymer battery, arduino pro mini with the ADS1115, xbee series 2 and a Midori Precisions linear sensor…essential a variable resistor up to 1K. Trees…[Read more]
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neilh20 posted a new activity comment 7 years, 10 months ago
I’m working with a variety of models – the base specification has been 0.1%FS TEB (Full Scale Total Error Band) with acceptance testing for a 10C shift in water temp across a diurnal cycle. The spec has been to accurately measure low levels at about the 0.2-1foot mark of water in summer – with a hydro-graph range of 0-10feet.
Initially we used…[Read more] -
neilh20 posted an update 7 years, 10 months ago
For anybody at AGU in San Francisco interested in sensor type technology, there is Tech Mixer open invite from
http://www.schmidtmarine.org/events
December 15th, from 6:00 p.m. to 9 p.m – 101 THE EMBARCADERO, SUITE #118 , SAN FRANCISCO, CA 94105
https://www.google.com/maps?q=101+The+Embarcadero+Suite+118+San+Francisco,+CA,+94105+United+States -
neilh20 posted a new activity comment 7 years, 10 months ago
H52G Water and Society:
Water Resources Management
and Policy in a Changing World V
10:20 A.M.–12:20 P.M.
Room 3002, Moscone West -
neilh20 posted a new activity comment 7 years, 10 months ago
The remote access lectures have been posted
https://fallmeeting.agu.org/2016/files/2016/11/On-Demand-Fall-Meeting-Sections.pdf -
neilh20 posted a new activity comment 7 years, 10 months ago
Thanks for the reference, I’ll look you up. I haven’t got a ticket yet as its out my pocket
Tere is a Tue 6:30pm-8:30 networking http://thrivingearthexchange.org/fall-meeting-2016/
that I’m thinking of but sounds like that will be before you get there. -
neilh20 replied to the topic RS485/Modbus RTU Transducers in the forum Environmental Sensors 7 years, 10 months ago
So to query any piece of equipment over a protocol, there are two parts – the physical layer and the data link layer protocol.
https://en.wikipedia.org/wiki/OSI_model
For the nanolevel it specifies physical layer as RS485 (for other equipment it may be the customer SDI-12)
For Keller products the modbus binary “data link layer” there is a document…[Read more] -
neilh20 replied to the topic RS485/Modbus RTU Transducers in the forum Environmental Sensors 7 years, 10 months ago
I received my dual relay board,
* AtomicMarket.com: 5V Two 2 Channel Relay Module With optocoupler
* SunFounder: 2 Channel DC 5V Relay Module with Optocoupler Low Level Trigger Expansion Board
and the code to drive the relays is pretty simple and is…[Read more] -
neilh20 replied to the topic ISE Nitrate Electrodes for continuous in-stream monitoring in the forum Environmental Sensors 7 years, 10 months ago
Hi Marion,
I don’t have any experience, and it would be great if you share what you find here.This is a topic the EPA is sponsoring – with a target of unattended for 3 months –
http://www.act-us.info/nutrients-challenge/And they have a short list
http://www.act-us.info/nutrients-challenge/Participants.php
regards -
neilh20 replied to the topic RS485/Modbus RTU Transducers in the forum Environmental Sensors 7 years, 10 months ago
Well my first post on this is to talk about the powering – not as sexy as the protocol, but a base requirement.
Since this is wired, each transducer is going to require power.
Getting powering right is ALWAYS a challenge for a circuit, especially solar powered, low power useage circuits. Its vital to understand the impedance of the power issues.…[Read more] -
neilh20 replied to the topic RS485/Modbus RTU Transducers in the forum Environmental Sensors 7 years, 10 months ago
Well my first post on this is to talk about the powering – not as sexy as the protocol, but a base requirement.
Since this is wired, each transducer is going to require power.
Getting powering right is ALWAYS a challenge for a circuit, especially solar powered, low power useage circuits. Its vital to understand the impedance of the power issues.…[Read more] -
neilh20 replied to the topic RS485/Modbus RTU Transducers in the forum Environmental Sensors 7 years, 10 months ago
Well my first post on this is to talk about the powering – not as sexy as the protocol, but a base requirement.
Since this is wired, each transducer is going to require power.
Getting powering right is ALWAYS a challenge for a circuit, especially solar powered, low power useage circuits. Its vital to understand the impedance of the power issues.…[Read more] -
neilh20 started the topic RS485/Modbus RTU Transducers in the forum Environmental Sensors 7 years, 10 months ago
Discussion on transducers that use “Modbus RTU” serial interfaces, typically half-duplex multi-slave RS485, but sometimes also full duplex point-to-point RS232 .
RS485, as physical link – is ideal for communicating to sensors that are 5~1000m away, with grounds that may be 8V apart.
Less than 15’/5m it would be nice to use USB – but that is a…[Read more] -
neilh20 posted an update 7 years, 10 months ago
I’m thinking of going to the AGU in SF Dec 12th?
I’m looking over the sessions. I live 40miles N of SF so fairly easy to go down for a day.
Anybody know some sessions they know about and recommend on terra firma monitoring.
Last year there was a networking presentation on newly launched http://thrivingearthexchange.org/-
I’ll be at the AGU meeting on Wednesday thru Friday. I’m also giving a presentation on Friday morning about EnviroDIY and our citizen science and education efforts.
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Thanks for the reference, I’ll look you up. I haven’t got a ticket yet as its out my pocket
Tere is a Tue 6:30pm-8:30 networking http://thrivingearthexchange.org/fall-meeting-2016/
that I’m thinking of but sounds like that will be before you get there.
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The remote access lectures have been posted
https://fallmeeting.agu.org/2016/files/2016/11/On-Demand-Fall-Meeting-Sections.pdf -
H52G Water and Society:
Water Resources Management
and Policy in a Changing World V
10:20 A.M.–12:20 P.M.
Room 3002, Moscone West
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neilh20 posted a new activity comment 7 years, 10 months ago
Hi Shannon, (response to your pvt msg – attempting to post here)
Yes I’ve got some RS485 transducers communicating. I’ve used the Sparkfun version in the past.
The key is that a protocol runs on top of the RS485 – sometimes called modbus – and some people represent it is a set of archaic concepts.
The full modbus may be useful in some SCADA apps,…[Read more] -
neilh20 posted a new activity comment 7 years, 10 months ago
Test.. having problems responding to msg
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neilh20 replied to the topic Modbus/12V to cellular in the forum Mayfly Data Logger 7 years, 10 months ago
Great. If you want cct comments I’d be happy to participate. I’ve used LM2623 +5V/1A, and also can do +12V
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Just came across a devices that maybe could make small distance measurements
Piezoelectric film – the problem might be calibrating it.
That is it might be able to show a change in trunk diameter based on stress applied to the film, but how easy would it be to translate to metric mm?
Also it doesn’t contain a temperature dependency…[Read more]