I think it's better to ensure the device definition accurately reflects its real capabilities, instead of trying to force-fit it into a generic model that is kinda/sorta correct.
Before the Nest, I had a Trane/Schlage themostat, so I've seen the generic implementation in action. It fits the Nest almost perfectly. It has separate heat/cool setpoints, Heat/Cool/Auto/Off mode selection, and fan control. The battery indicator also works. You've already broken out the other features (humidistat/home/away) into other children.
If I get the UI4 implementation to work I will share the results with this thread. Thanks for the insight!
Only two very small issues prevented it from working correctly:
D_HVACZoneThermostat1 expects to find fan status at “ModeStatus” not “Mode”.
My firmware doesn’t support luup.attr_get/attr_set, so the poll function would stop short. Commented those out (I believe they move the devices into the right category, which is something that doesn’t apply to UI4).
Installation instructions:
Download Watou’s code
Replace the I_Nest1.xml file with the attached.
Go to MIOS developers/luup files and upload all the files to Vera. Check restart luup when done uploading.
Go to MIOS developers/device tab, Create a new device with UPnpDevFilename = D_Nest1.xml, UPnpImplFilename = I_Nest1.xml
Click Create Device and it should do the rest.
You’ll need to input your login parameters and such and then it should create the child devices.
I just resolved a “low battery” issue with my Nest. I got it for christmas and it’s been working great. Last week it disconnect from the web because it had a low battery error (hey disconnect the unit from the network if the battery gets too low). After searching the web… I found that the problem is that when the nest is connected with the standard R,Y,G,W wires, the only time the Nest will charge the battery is when the furnace/AC is running. Otherwise they “pulse” the system to maintain battery charge. it so happened with mine that we had several warm days and they downloaded a new firmware version (which drained my battery).
The solution is to run the “C” wire which is the common wire from the 24V to your thermostat… My system had a “C” output on transformer and I fortunatly had an extra wire “blue” so after connecting the “C” the battery has the common side of the 24v and can maintain the battery charge regardless if the system is running. Moral of the story… If you’re installing a Nest try to get the “C” connected if at all possible.
This is probably the only serious design flaw I am aware of with this unit. In the absence of a common wire the Nest will cycle your existing system in order to pulse charge the battery. How this idea made it past an engineering review I will never understand. Also the fact that they make no mention of this on the compatibility checker site is another poor decision. I refused to submit my heating/cooling systems to this extra wear and tear for the sake of a battery. For my 1st floor unit running a C wire was impractical so I decided to repurpose the fan wire as C, thus giving up the ability to run the fan in isolation. For the 2nd floor unit I was able to run a C wire. There is also the Add-A-Wire but I have no experience with that device.
Two small suggestions for the next practicable version:
add an option to control logging level, so that someone who wants to see the old style of verbose logging, i.e. log all actions/variables regardless of changed or not, can do so (the minimal logging can be the default setting)
add some way to see the status of ModeState in the GUI - although changing the Next icon to orange or blue would be nice, I understand if that is not possible, so just a textbox or similar would be great
[quote=“bobk, post:165, topic:171456”]Two small suggestions for the next practicable version:
add an option to control logging level, so that someone who wants to see the old style of verbose logging, i.e. log all actions/variables regardless of changed or not, can do so (the minimal logging can be the default setting)
add some way to see the status of ModeState in the GUI - although changing the Next icon to orange or blue would be nice, I understand if that is not possible, so just a textbox or similar would be great
I am thinking I would add a “Logging” variable to the main Nest account icon, which defaults to 0. If you set it to 1, the plugin will simply set variables that haven’t changed, like before, and that will create the log output you are looking for. Future values besides the ones above will have new meanings (if needed).
Also, I think I could add the ModeState below the heat and cool setpoints in the device layout. I think there is enough room. If not, I will put it under the Fan Mode. Sadly I cannot show the current temperature in large text and also change the device icon (unless there is some json-fu I’m unaware of).
Please let me know if you have better ideas for these proposed changes.
I will try to have a 1.0 of the plugin submitted this coming week. And also, thank you very much, Bob!
actually, this is supposed to be a “feature” of Nest. My Z-Wave Trane tstat requires a C-wire, and cannot operate without it . By adding a chargeable battery, Nest is able to be compatible with more systems, as it doesn’t require a C-wire, albeit a C-wire is recommended.
I get the point that if you have a C wire you are no worse off than if you instead had one of the other tstats that full stop require a C wire. Yes of course people who have a C wire already, there is no difference. From Nest’s perspective they probably think they are doing their customers a favor by allowing them an additional option to get away with no C wire. But I’d love to see the extended testing that they did on various models of new and old HVAC systems to gauge the wear and tear impact of pre-cycling the system. I can’t see how they did such testing. Also curious what the HVAC manufacturers will say about this, whether their systems are resilient to this or whether they will use this as an excuse to deny warranty claims for certain components. As an infrastructure software engineer my moderate indignation is a combination of bewilderment at the engineering risk they are taking combined with their failure to let people know clearly know pre-purchase that they are on the losing end of such a risk. When my system precycles for heat, the flue fan starts up, in order to get an updraft prior to the burners lighting. For AC there is no precycle, the compressor comes on immediately. Doing this 10 or 20 times a day, if it doesn’t break my system after a couple years, it will certainly use up some of the money/energy savings the Nest supposedly generates from its other innovations.
The proposal for the Logging variable makes sense to me.
For the ModeState indication, do you have the ability to set the color of text? Perhaps in addition to displaying the text value of ModeState, could you also set the color of the text to orange, blue or black/grey correspondingly? Just a suggestion, if you can’t, you can’t.
I agree with you that a bad idea is a bad idea, and running an entire HVAC system to charge a tiny battery is a bad idea. I had a colleague once who thought it was a good idea to execute a script for the purpose of syntax checking it, damn the side effects. That was indeed a bad idea. Sometimes the “novel” solution just isn’t the good solution.
[quote=“watou, post:170, topic:171456”]I agree with you that a bad idea is a bad idea, and running an entire HVAC system to charge a tiny battery is a bad idea. I had a colleague once who thought it was a good idea to execute a script for the purpose of syntax checking it, damn the side effects. That was indeed a bad idea. Sometimes the “novel” solution just isn’t the good solution.[/quote]That’s not how power stealing is intended to work. The idea is to draw just enough power from the transformer to charge the battery, without triggering the relays that operate the furnace.
Some furnaces built with solid state logic are too sensitive and will operate anyway. Nest did not invent power stealing, some Honeywell stats and others work the same way.
Google “power stealing thermostat”, there’s a lot of info out there about it.
[quote=“watou, post:166, topic:171456”]Also, I think I could add the ModeState below the heat and cool setpoints in the device layout. I think there is enough room. If not, I will put it under the Fan Mode. Sadly I cannot show the current temperature in large text and also change the device icon (unless there is some json-fu I’m unaware of).
Please let me know if you have better ideas for these proposed changes.[/quote]
Version 1.0 of the Nest plugin has been published in app store. It adds the ModeState text (Heating, Idle, Cooling, FanOnly, Off) below the heat and cool setpoints, adds an optional [tt]Logging[/tt] variable to increase log output if set to 1, two new triggers for when the heat setpoint is set lower or cool set point set higher than specified temperatures, and fixes two minor bugs. Please see the README.md for more information at [url=http://cocu.la/vera/nest/README.md]http://cocu.la/vera/nest/README.md[/url].
Please let me know if you have any issues with this release. Thank you!
[quote=“chuck1026, post:176, topic:171456”]I am wondering… since Vera 3 doesn’t seem to “auto update”, what is the best procedure to update a plugin and not disturb the device ID, etc. ?!?
Chuck[/quote]
Follow the instructions in this post:
[quote=“TheGadgetGuy, post:179, topic:171456”]Updated to 1.0. So far so good. Excellent plugin!
It is because of this plugin that I have two Nest 2.0’s so far![/quote]I would have done the same already if work and several other projects hadn’t been getting in the way! My Wayne Dalton one is soon to be history thanks to a $200 lowes gift card that I’ve been saving for this (thanks corp credit card reward scheme)
