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Weather Station Hardware => Remote Weather Monitoring => Topic started by: Flag on March 14, 2011, 06:03:06 AM
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Yes totally different ball game, some of the main issues as it's not simply a case of walking out into the back yard and putting things right.
- Primary DC Power source, 5-6 volt AND 12 volt generally solar provided
- Secondary / backup power requirements
- Security of the hardware, infrastructure, sensors etc
Really all comes down to power, security and sensor integrity as if any of these fails then you have no data to download regardless of what communication system there is.
Even if comms fails and you are unable to get to a station for months on end but then still able to download the data with 100% integrity then all is good.
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Yes totally different ball game, some of the main issues as it's not simply a case of walking out into the back yard and putting things right.
- Security of the hardware, infrastructure, sensors etc
And the associated one that sometimes a remote site will have no shelter or building (eg not even a wooden shed) in which to house the equipment. So a good weatherproof box/shelter can also be needed here. The Davis 7724 Complete System Shelter is a good quality part if you need to house a standard Vue or VP2 console but pretty expensive for what it is.
And you also need to remember that Davis (if indeed it's a Davis system) advise that the console should be located at least 5-10m away from any Vantage transmitter in order that the console receiver circuitry is not overloaded with signal. So it's not advisable to mount the console box on eg the same tripod/pole/post as the ISS.
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"Infrastructure" is what houses the equipment and even a davis complete system shelter is not something that is actually secure. The "infrastructure" will probably cost more than the entire station hardware and associated power systems put together.
Mounting the ISS in a stainless steel enclosure separate to the other hardware is one way to kill off signal strength then again have setuos with ISS/Envoy/comms/power etc all mounted in the same stainless steel enclosures with absolutely no signal or related issues.
With regard Dvais systems this is where the Envoy comes into its own as a Davis console (VP2 or Vue) in a remote system is really a waste of space.
Still no amount of infrastructure totally proves complete security and this especially relates to the rain collector, anemometer, Temp/humidity and solar/UV sensors. For 2 leg vermin these sometimes require an 8 foot barbed toped fence enclosure.
For other vermin then the requirements differ but still important considerations.
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With regard Dvais systems this is where the Envoy comes into its own as a Davis console (VP2 or Vue) in a remote system is really a waste of space.
I'm not 100% sure about this. An Envoy will fit into the much cheaper 7728 shelter, so there's certainly a good cost argument in favour of the Envoy.
Also the Envoy will effectively reboot itself fully should there be any power outage at the remote site (eg more short winter days of gloomy weather than the solar PSU installed can accommodate), which the standard console won't do.
The bit where I'm unsure is that you may be visiting the remote site occasionally to run checks, make adjustments etc. While you're there for just a very limited time the quickest and easiest way of checking sensor readings is with the LCD display of a standard console. I guess the obvious answer is to use an Envoy as the installed console at the remote site and then just to take eg a spare Vue or VP2 console with you when visit the site (assuming that it's a wireless Vue/VP2 system that you have set up).
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With regard Dvais systems this is where the Envoy comes into its own as a Davis console (VP2 or Vue) in a remote system is really a waste of space.
I'm not 100% sure about this. An Envoy will fit into the much cheaper 7728 shelter, so there's certainly a good cost argument in favour of the Envoy.
Also the Envoy will effectively reboot itself fully should there be any power outage at the remote site (eg more short winter days of gloomy weather than the solar PSU installed can accommodate), which the standard console won't do.
The bit where I'm unsure is that you may be visiting the remote site occasionally to run checks, make adjustments etc. While you're there for just a very limited time the quickest and easiest way of checking sensor readings is with the LCD display of a standard console. I guess the obvious answer is to use an Envoy as the installed console at the remote site and then just to take eg a spare Vue or VP2 console with you when visit the site (assuming that it's a wireless Vue/VP2 system that you have set up).
Yes that's about all I use a console (display) for.
Then again the very first thing that is ever done (after opening the door) before any form of maintenance or checking is to connect a laptop and download the data just in case something stuffs up. While connected it's easy to check sensors etc
Used to use a PALM for just in case download/backups once but now use a small laptop which allows much better access and checking capability.
With regard wired v wireless? My preference is always wireless due to lower power and secondary systems which can be hung off the same ISS including backup anemometers and multiple data linked systems.
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For the Envoy outside, Davis has some enclosed shelters that it will fit in.
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For the Envoy outside, Davis has some enclosed shelters that it will fit in.
Yes they might be alright outside in the backyard but not real suitable or secure out in the middle of no where.
One could undo any Davis shelter/enclosure with a wrench or pair of pliers in a few seconds and walk away with it.
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With regard wired v wireless? My preference is always wireless due to lower power and secondary systems which can be hung off the same ISS including backup anemometers and multiple data linked systems.
Agreed!
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Around here, I think I'd go with a VP2 or mebbe a Vue ISS on top of a 12' or taller 6x6 or utility pole. Wireless would be OK, but a wired VP2 ISS means no battery to change.
Just down from the ISS, a side mount solar panel sized for the load calcs.
Then, on the bottom, 4 or 5 feet up, a NEMA 4x lockable box for the console/Envoy, batteries, and whatever wireless device is needed. With external antennas (box top or farther up the pole), it could be stainless, but a nice Hoffman or Allied Moulded Products fiberglass cabinet would be OK.
I might put a couple of screened louver plates on the box for ventilation, and perhaps allow in the power calcs for a small 12vdc fan and an internal thermostat.
PG&E has an RM Young wind station with a similar setup on the street just down the hill that's never been messed with.
FWIW, I have 5 similar boxes out in the open, for well control, with box top 400 MHz mobile omni antennas, and the boxes have never been disturbed. On is right on the street. Come to think of it, it's not even locked...
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Around here, I think I'd go with a VP2 or mebbe a Vue ISS on top of a 12' or taller 6x6 or utility pole. Wireless would be OK, but a wired VP2 ISS means no battery to change.
The Vue ISS has yet to prove itself in a backyard situation before anything serious regarding remote systems. Basically the Vue has not been around long enough to do this. Underneath the Vue all those slits and slots might have an attraction for all sorts of bugs in the wild?
A remote VP2 ISS setup should always have external power regardless of the backup battery and/or solar. With a properly setup ISS with external power the plan is it should never need the backup battery etc.
Just down from the ISS, a side mount solar panel sized for the load calcs.
One thing that is a negative with 5-6V DC systems is the lack of a selection of solar panels and even more so an almost complete lack of 6v solar regulators.
I might put a couple of screened louver plates on the box for ventilation
Also include a sign saying "Insects and bugs enter here" :grin:
and perhaps allow in the power calcs for a small 12vdc fan and an internal thermostat.
Air-conditioning :-) now that is a luxury for any small solar system. Enclosures and cabinets should be designed on natural convection cooling principles
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I might put a couple of screened louver plates on the box for ventilation
Also include a sign saying "Insects and bugs enter here" :grin:
Hence the screening...
and perhaps allow in the power calcs for a small 12vdc fan and an internal thermostat.
Air-conditioning :-) now that is a luxury for any small solar system. Enclosures and cabinets should be designed on natural convection cooling principles
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Until I retired, the last 16 years I was Telemetry and Instrumentation Tech for the local municipality. I designed, built, programmed, installed and maintained 50 sites/RTUs/DPCs for the Utilities Department. They included the reservoir pipeline, treatment plants, pump stations (fresh and wastewater), and 400 MHz links, 928/952 repeater systems, leased and private copper, and fiber.
If the site was in the open, I generally included ventilation and a small fan. When it gets to the mid 90s and higher, the internal cabinet temps can get >130. So, I set the fan thermostat to around 100.
Because of the higher wattage radios (5 watts in some cases) and short duty cycle (xmit every 30 seconds) n some cases, the solar powered sites were beefy. One with 2 transceivers had about 150 watts of panels, and a 50 AH battery, to carry it through long winter nights and a few days of overcast.
A li'l 12vdc fan didn't add much to that. Maybe 1 AH per day or so. :)
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But telemetry sites like that have some serious internal heat sources such as fairly high power radio and associated hardware with fairly substantial heat sinks etc so is a totally different ball game to typical weather station hardware where there is bugga all heat generated internally and any convection type heating can be controlled by enclosure design rather than wasting valuable power resources running fans etc.
The idea is to keep things as simple as possible.
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Also the Envoy will effectively reboot itself fully should there be any power outage at the remote site (eg more short winter days of gloomy weather than the solar PSU installed can accommodate), which the standard console won't do.
Yes Envoy will re-boot but would not call it fully (as such) as the station time (& date) will generally not be correct which then corrupts the database (& WeatherLink.com) with invalid archive times.
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Yes Envoy will re-boot but would not call it fully (as such) as the station time (& date) will generally not be correct which then corrupts the database (& WeatherLink.com) with invalid archive times.
Yes that's all true. Using the Envoy certainly isn't a perfect solution and does highlight that Davis really should change the way that the clock circuit is powered to a design where just the clock chip can be run off a small coin battery and so continue to keep time even when the main power is out.
But I'd still maintain that having an Envoy is often better at a remote site than the standard console. With the std console you can guarantee that after a power outage then you'll get no more weather data from the site until a visit in person to reset the console.
But with the Envoy and if you're using an application that just relies on loop data, which isn't time-stamped, (or the WLIP current conditions data, which also seems to have no time-stamp) then the Envoy data stream will resume perfectly usefully after a power outage. The same might well apply to something like a MeteoHub application, though I'm no expert as to whether or not the PC can be set to reboot and reset automatically) It's only when you have an application that totally relies on using the archive data that there's a problem with both std and Envoy consoles.
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Yes definitely the Envoy over the console as the envoy will at least boot through without assistance but ...
To highlight the time issues pull the power on a Envoy/WLIP sometime and observe how it latter starts up. The WLIP page will show the Envoy time which will be off depending on how long the system was powered down. The variables (Hi/Lows etc) are all reset and reflect the envoy time (which is of course is not the right time). The Envoy date does not reflect on the data pages anywhere so doesn't come into the equation.
Basically an Envoy re-starts from the point in time where it stopped which could be 1 minute or 1 week ago.
What I have noticed thou is that the time appears to re-start on a whole hour with zero minutes?
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My summary comments:
#1 rule with a remote Davis station is to never loose power
Console or Envoy loosing power basically results in invalid or no data and essentially invalid data is no data
Current console/envoy battery backup is inadequate with WLIP
#2 rule is never loose power
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My summary comments:
#1 rule with a remote Davis station is to never loose power
Console or Envoy loosing power basically results in invalid or no data and essentially invalid data is no data
Current console/envoy battery backup is inadequate with WLIP
#2 rule is never loose power
In this vein, I run my console off a Netbook (3 hr battery) which is plugged into the UPS. As is the console. No power issues in almost two years. Despite long (10-12 hr) outages over the years.
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In this vein, I run my console off a Netbook (3 hr battery) which is plugged into the UPS. As is the console. No power issues in almost two years. Despite long (10-12 hr) outages over the years.
Is this a WLIP or serial logger?
Obviously you have mains power?
Is this a remote setup?
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USB logger. :)
Mains power most of the time.
400 miles from home in the Monashees.
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USB logger. :)
Mains power most of the time.
400 miles from home in the Monashees.
:eek: now that is confidence in a USB logger
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Honestly? USB has been ZERO problems. Telco is the biggest problem so I'm installing packet radio real soon. No more 19.2 kbps. :) I can go to hourly updates rather than twice a day.
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#1 rule with a remote Davis station is to never loose power
#2 rule is never loose power
I don't disagree in the slightest with the sentiment or objective here.
However, in the real world and at sites where no mains power is available, without spending a large (and potentially unacceptable) amount of money on overengineering eg a solar/wind PSU then there _are_ going to be occasions when the power drops out at remote sites - potentially for several days at a time. This is going to be especially true during mid/high latitude winters. The question then is how best to deal with this situation.
Unavoidably this situation is going to lead to some loss of data. But then the aim of the remote AWS design should presumably be such as to minimise these data losses. And if you are going to be using a Davis station in this situation (as still, arguably, the best choice for a cost-effective AWS) then I'd suggest that the best solution is based on:
1. Using an Envoy console (so that it will reboot automatically when power resumes);
2. Using Loop data as the primary source of weather data (because it avoids timestamp issues);
3. Using a 1-2W miniature PC to preprocess the data at the remote site because, realistically, this is the only way to control the data flow and assure its validity (eg vs time). Of course this PC also needs to be programmed to reboot automatically into the correct processing configuration and resume data uploads as soon as possible after a power outage.
(Of course the Davis Vantage Connect product looks like being an alternative way of meeting the same criteria, although you're then locked into the Davis way of doing things and the associated plan prices.)
So my rules would be slightly different:
[1] Try, as far as is practicable and affordable, to reduce the chances of a power outage to an absolute minimum;
[2] Use a data architecture that does allow automatic rebooting (albeit with some data loss) should a power outage happen in practice.
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Running WLIP remotely can be the killer if you loose power and yes one has to way up the importance of the data v the PSU installed. The way I look at it the Console/Envoy battery backup was never designed with the WLIP in mind. The two issues I see with power loss is 1) ongoing r/t access to the system and 2) ongoing data availability and integrity, these are 2 distinct different issues.
I have some issues with say an Envoy booting up with invalid time and see the (possible) means to correct this rather messy and generally not practical?
Not having live access to the system might be acceptable in some instances as long as the on-going integrity of the data can be guaranteed. Maybe it would be more simplistic to run a second Envoy and serial logger to ensure on going data integrity which on backup battery can be made to run for months even if it means runing with a longer archive interval to achieve this?
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Honestly? USB has been ZERO problems. Telco is the biggest problem so I'm installing packet radio real soon. No more 19.2 kbps. :) I can go to hourly updates rather than twice a day.
They give me ZERO problems as well ....... don't use them. Guess I'm not a USB logger fan?
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Hw could you possibly know if you do not use a USB logger?
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Like I said I don't use them, never said I have never used them, just gave them away a long time ago. Probably got one in the cupboard in original packaging, what would it be? about 10 year old, maybe more?
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I'll give you 10 bucks for it.
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I'll give you 10 bucks for it.
Worth that much hey ;)
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Maybe it would be more simplistic to run a second Envoy and serial logger to ensure on going data integrity which on backup battery can be made to run for months even if it means runing with a longer archive interval to achieve this?
Actually that's exactly what I've been doing at one site to try to cover midwinter power outages. It is an unattended field site where access is sometimes difficult (because of very muddy/boggy ground in this instance, in fact) but not so remote that - weather permitting - it can't be visited every 2-3 weeks for a manual download if absolutely necessary. So I run this with a 15 minute AI. Obviously if I felt that I needed to stretch this to say 6 weeks then I could use a 30min AI - as suggested - and so maintain some level of backup data continuity. For this sort of occasional, manual download, the USB logger is fine. But of course any live data feed is lost.
I'm coming round to the point of view that if you can only afford a limited solar/wind PSU then the Vantage Connect type of system is probably the best option. I don't necessarily mean using the VC itself but a similar principle where, other than the console/serial logger itself, then the system sleeps for most of the time and just wakes a cellular modem every 5/15/60/whatever minutes to transmit a block of data and then returns to sleep. Although you lose literally-live data with this sort of configuration, 5/15/60 minutes updates are still sufficient for many 'live'** purposes and the power consumption by VC-type systems is as low as you're ever going to get - it should be compatible with even relatively modest solar PSU's (bearing in mind that the VC is powered by a 2.5W panel, though I have my doubts as to whether this is quite enough).
(** There's a whole discussion here about what we might mean by live data - ie is it literally every 2-3 sec updates or would every 5 minutes qualify?)
Finally, as Flag mentioned, another tactic to assure data continuity is to ensure that the logger keeps logging as long as possible even if a power shortage threatens other components of the system. This is actually what I do with an IP logger which is fed from a separately switch 12v supply that only drops out after everything else (eg cellular modem) has dropped out. So the last 10-20% of available battery capacity is used solely to keep the logger running. So I should amend my rules to:
[1] Try, as far as is practicable and affordable, to reduce the chances of a power outage to an absolute minimum;
[2] Feed the console/logger from a separate DC supply such that it is the last component of the data infrastructure left standing before the power finally drops out.
[3] Use a data architecture that does allow automatic rebooting (albeit with some data loss) should a power outage happen in practice.
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All this raises a specific issue of how to make the most out of the Davis battery backup so have started a specific thread.
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I'll give you 10 bucks for it.
Worth that much hey ;)
Sure - then I will hack it to add an SD card. :)