Topic: Weather Station for Home Automation

[apardal]

Hi!

First time poster here. My name is Andre, 33 years old, and I'm from Sintra - Portugal. These past few weeks I've been reading a lot about weather stations. I've just started this because I've built my house and I need some sensor input to make my house "intelligent" with my home automation system.

I've installed an iDom system which is proprietary (I may regret having made this decision) because it was the only system that my electrician worked with. I think it is KNX based and it has a Gateway with RS232/485 connectivity through RJ12 port (6P6C) - Modbus.

I'm a civil engineer. Bricks and concrete are my thing. I know nothing about weather, very little of programming, and I can work the hardware with soldering and stuff.

What I need for my home automation system is (purpose):

- rainfall (watering the garden)
- wind direction, speed and wind gust (windows shutters emergency open >30 mph wind gust)
- sunset, sunrise (illumination)
- temperature (climate control)
- humidity (ventilation)

With this in mind, I bought a Fine Offset weather station (Watson W-8681) a few years ago, when I wasn't aware of the home automation system that I would install. This weather station does almost everything I need, apart of sunset/sunrise, but I can install a sensor connected directly to the home automation collector input for cheap. What I don't know is if it is possible for my WS to "talk" with the home automation system.

I've downloaded the Modbus integration manual for my home automation system ( http://www.domatica.ptservidor.com/support/download_attachment.php?kb_att=24 ) and I understand how to do it, but I'm not sure if the data output from the WS will be "readable".

The home automation system provider recommends the use of the Davis Vantage Pro2 which is already integrated in this system, but t the cost of this weather station in Portugal is quite high as per customs and taxes oblige (costs over 800USD).

I don't know if the Vantage Vue would work and if I need some accessory from Davis to connect the console to the home automation system gateway.

Thanks in advance for your time reading this and let me know if there is any other aspect of my home automation system that may help you help me!

Best regards

[johnd]

This looks quite a complex question. But if I've understood correctly and Modbus is the only gateway interface into your automation system then:

1. Davis don't themselves have a station with a Modbus interface, whether the Vue or any other model;

2. Ocean Controls make a Modbus interface card for the RS232 output of a Davis Weatherlink logger (which can be fitted to any Davis model including the Vue). We have details on our website at http://www.weatherstations.co.uk/modbus.htm

3. This would presumably provide the appropriate interface at the electrical level, but somewhere in your automation system some code would need to be written to read the relevant Modbus registers of the OC card and deliver the weather readings when and where needed. This presumably needs someone with some expertise in programming your automation system - the OC card can make the weather readings available in the right sort of generic format but it still needs a logic interface into the automation processes.

[apardal]

Hi!

Thank you for your reply.

I'm not sure if Modbus is the only interface my automation system supports. I'll try to contact them tomorrow to find out.

Which is the output interface of the Davis Weather Station?

You can say for sure that I need the Davis Weatherlink logger for this purpose? I was hoping some kind of DIY cable it would make it less expensive, but I've read that Davis has updated their models making this impossible...

I have the project builder software that allows me to create drivers and procedures for modbus integrations... If I can get the data to reach the gateway I think I can set it up.

Do you know if the Vantage Vue data output is the same as the Vantage Pro2?

[Skywatch]

The Davis Vantage Pro2 is a great station and they make a version of WeatherLink for home automation.

The Vantage Pro2 plus has solar sensors which are a better method of illumination indication.

Vantage Pro2 plus runs for 627$ Scaled instruments

Didn't see the home automation module on Scaled or Rainman unless I missed something. But this is it
http://www.amazon.com/gp/aw/d/B000WBN9SW?pc_redir=1404530604&robot_redir=1

[johnd]

You can say for sure that I need the Davis Weatherlink logger for this purpose? I was hoping some kind of DIY cable it would make it less expensive, but I've read that Davis has updated their models making this impossible...

It's a slightly complicated situation but I'd say that in practice the only tried and tested solution is to use a Davis Weatherlink serial logger - this gives the RS232 output that the OC card requires as an input. Also, I think it would be wrong to think of this Modbus approach as a low-cost one. It is fairly cost-effective, relative to other commercial/industrial solutions as would normally use a Modbus interface, but it's certainly not low-cost in the sense of eg a Fine Offset station. Remember also that the OC card is just a bare card and would need its own eg 12v DC supply.

I have the project builder software that allows me to create drivers and procedures for modbus integrations... If I can get the data to reach the gateway I think I can set it up.

OK. If you were to use the KTA-282 card then you can download the documentation for it, which includes eg register specifications - there's a link on the page on our website that I referenced previously.

Do you know if the Vantage Vue data output is the same as the Vantage Pro2?

Yes (but obviously only for those sensors that the Vue supports).