Opentherm Gateway

This Forum is about the Opentherm gateway (OTG) from Schelte

Moderator: hvxl

Re: Opentherm Gateway

Postby hvxl » Fri Dec 20, 2013 5:49 pm

dirkjanw wrote:Any idea what could cause the gateway to intermittently need VR=2 or VR=3? Lately I regularly (every few days) need to toggle it for communication to be restored. The thermostat will report 'No communication' and no boiler messages are being decoded at that moment. So it seems the voltage is very critical there.

Actually, the reference voltage is not at all critical for the boiler interface. The current detection is done by R2 and OK1B. If the voltage over R2 goes above the voltage required to light the internal LED of OK1B (typically 1.2V), the output of the OK1B (pin 5) will be pulled high. Otherwise R4 pulls the output low.

The voltage over R2 is related to the current from the boiler. For a logical low level (5-9mA), the voltage over R2 will stay below 0.9V. For a logical high (17-23mA), OK1B will limit the voltage to 1.2V. That means 12 mA will go through R2, the remaining 5+ mA lights the LED.

When OK1B isn't activated, the output is pretty much 0V. When it is activated the output goes to something like 3.5V. A really substantial swing. The output of OK1B is the input to the voltage comparator. So that should always work, no matter whether the reference voltage is 0.625V (VR=0) or 2.5V (VR=9), or anything in between.

If R4 is too small, the output may not go high enough and lowering the VR setting may help. But then there would be no need to ever raise it again. If any component in the boiler interface is faulty, changing the reference voltage would not make a difference. So I can't come up with a scenario that would explain the behavior you are observing, unless there's a loose connection somewhere. I would probably start by resoldering all component leads of the boiler interface. Next step is to measure voltages in specific places. Do you have a voltmeter? Is your IC1 in a socket so you can easily remove it?
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Re: Opentherm Gateway

Postby hvxl » Fri Dec 20, 2013 9:04 pm

Additional question: When you need to change the VR setting, are you sure the old one is still in effect? Next time it happens can you first run the commands PR=V and DP=9D and report the results?
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Re: Opentherm Gateway

Postby dirkjanw » Fri Dec 20, 2013 10:10 pm

hvxl wrote:Additional question: When you need to change the VR setting, are you sure the old one is still in effect? Next time it happens can you first run the commands PR=V and DP=9D and report the results?


Next time it happens, I'll check. Needed to put it on VR=4 yesterday to make it work; VR=2 and VR=3 didn't cut it. Regarding the components and the socket: I bought the kit from Roland on opentherm-gateway.com and from the top of my head it is socketed so removable... Last time I handled my multimeter is about a decade and two continents ago, so should probably order me a new one over the weekend ;) Gives me the opportunity to resolder it too. However, due to the fact that resetting the voltage fixes the issue (it installed near the boiler, I telnet in) and yesterday I needed to go to VR=4 makes me think something is temperature sensitive (that should not be) or something... But my electronics knowledge is failing me there.

On a side note: I did not install the (external) LEDs. Can this in any way hamper operations? Thanks!
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Re: Opentherm Gateway

Postby hvxl » Sat Dec 21, 2013 11:32 am

dirkjanw wrote:I did not install the (external) LEDs. Can this in any way hamper operations?

The LEDs are completely optional. They do not influence the operation of the gateway, unless there's a short circuit somewhere. To totally rule them out, you can configure all LEDs to some unused function. I.e.: LA=Q, LB=Q, etc.
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Re: Opentherm Gateway

Postby rtenklooster » Sun Dec 29, 2013 12:04 am

Schelte,
I have been running the gateway for a month or two now.
OTG -> Raspberry pi with remserial -> php webserver
Combined with a vision modulation touch and a atag a244EC

I wanted to let you know that it's running like a charm. No hanging or what so ever.
Even after i just disconnect the power, of both the rasp. and the otgw its booting and working in a few minutes!

I am very very happy about most of it :) Except half degrees on my thermostat.

So thanks a lot for your work!
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Re: Opentherm Gateway

Postby trie » Thu Jan 09, 2014 6:21 pm

rtenklooster wrote:Schelte,
OTG -> Raspberry pi with remserial -> php webserver


An alternative for remserial which you apparently have to compile yourself is "socat" which is a standard package on Debian. It has A LOT of options.

Example on server (transmit data from ttyUSB0 via UDP to other host):
$ socat OPEN:/dev/ttyUSB0 UDP-DATAGRAM:client.host.name:6000

Example on client (put data from ttyUSB0 in pipe on /tmp/socat.ttyUSB0):
$ socat -d UDP-RECV:6000 pty,link=/tmp/socat.ttyUSB0,raw,echo=0

Also, I'm working on remote thermostat presentation and manipulation software. See screenshot here:
image.jpg
image.jpg (28.79 KiB) Viewed 14252 times

It's currently running on my Raspberry and gives a nice interface to the Thermostat settings (optimized for iPhone/mobile phone). It also gives live feedback with status icons about the current status of the boiler. I'm also going to implement basic programming and more info/settings but as for now it's working great for my situation. I'm not sure what other users are using for their OTGW interaction?
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Re: Opentherm Gateway

Postby Joep » Sat Jan 11, 2014 9:37 am

trie wrote:I'm not sure what other users are using for their OTGW interaction?

For two months my OTGW is in production. :P I own the Honeywell Vision Touch thermostat as well and wrote a little script to reset to the program when the override time expires which I set on my phone.
The back-end of my domotica system is self written in Ruby and the front-end is written in PHP for back-end calls and HTML5/jQuery for the GUI. I disliked all the interfaces I found on the Internet, I want it to be sleek and modern, so I wrote everything myself:

Image

The Central Heating Mode, Domestic Water and Flame status are realtime. When the boiler pressure drops below 1.2 atm I get a warning in the status bar. Therefore I don't have to run upstairs and check every month (I'm getting lazy with al this automation).

My girl LOVES it! :D She can set the thermostat higher with the comfort of lying under her blanked at the couch watching cheesy TLC shows :lol:
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Re: Opentherm Gateway

Postby dennie » Sun Jan 12, 2014 2:48 pm

Joep that UI is awesome! Are you willing to share your code?
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Re: Opentherm Gateway

Postby Joep » Sun Jan 12, 2014 9:03 pm

The code is custom build on my selfmade domotica system. It's not a framework, so you have to change and fiddle a lot to make it work on standard systems or other home-brew back-ends. Shown screen is just the OTGW part, I have everything incorporated, from lights, door-sensors, weather station, movie watch list information to Sickbeard upcoming TV-shows. But showing screenshots is off topic.

I would like to share it with the forum members here, but I used and edited artwork found via Google and don't have the license for it, so I think I cannot make it public. :cry:
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Re: Opentherm Gateway

Postby dennie » Sun Jan 12, 2014 11:37 pm

I also have a custom build domatica system but the only thing that is missing is a good UI, so I don't mind that I have to fiddle in your code. I just want to see/learn how you created the UI part.
Maybe it's an idea to put the files into a zip file (maybe with a passsword) and then upload it on a public dropbox link or different sharing site?
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Re: Opentherm Gateway

Postby rtenklooster » Sun Jan 19, 2014 12:32 pm

I have a php / jquery mobile frontend.
Advanced scheduling, temp rules, permanent rules etc.

Image
Image

It is intergrated in my domotica system as known from http://www.nodo-domotica.nl
But Joep, i realy love your webapp! Big compliments. I would love to use your design and layout.
So if you are willing to share..
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Re: Opentherm Gateway

Postby phoenixb » Mon Jan 20, 2014 4:06 pm

Hello,

Little question I hope that I can ask it in this subtopic.
When I connect a USR-RS232-E45 direct to the RS232 side of the OT gateway (with an external power supply) and wants to connect with the Otmonitor (last version) I getting no connection.
Default port on the converter in this case is 966 and I have setup the converter in the mode TCP server but i getting no connection.
Now the question is someone have made the same config and see I something wrong?

I like to hear it.
Regards,
DJ
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Re: Opentherm Gateway

Postby Joep » Mon Jan 20, 2014 6:52 pm

rtenklooster wrote:But Joep, i realy love your webapp! Big compliments. I would love to use your design and layout.
So if you are willing to share..


Thank you! I decided to create a webpage with my experience writing the back-end and this app. Then you can make it yourself with examples and I don't have to upload the used artwork I got from Google.
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Re: Opentherm Gateway

Postby rtenklooster » Wed Jan 22, 2014 1:10 pm

Joep wrote:
rtenklooster wrote:But Joep, i realy love your webapp! Big compliments. I would love to use your design and layout.
So if you are willing to share..


Thank you! I decided to create a webpage with my experience writing the back-end and this app. Then you can make it yourself with examples and I don't have to upload the used artwork I got from Google.


You already have this page? Or are you planning on making one? If youre finished please post a link.

For now i am busy connecting a arduino by serial to the gateway. This for a wireless connection to my server and intergrating it with my domotica solution.
Never used arduino and serial write / read before.

There is no other member who has connected a arduino to the gateway? I dont have to reinvent the wheel of course..
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Re: Opentherm Gateway

Postby dirkmans » Sun Jan 26, 2014 1:27 pm

@DJDive is it already working?
I'm also interested in a serial to ethernet converter
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