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Thread: Split System Air Conditioning suggestions?

  1. #11
    Automated Home Legend chris_j_hunter's Avatar
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    yep, 'tis a shame Serial interfaces aren't easier to manage ...

    we found, with many of our various machines (H&V units & controllers, garage-door operators, etc) there were terminal blocks under the covers that offered various options that could be brought into Cortex in various ways - via relays, digital inputs & outputs, 0-10V inputs & outputs ...
    Last edited by chris_j_hunter; 7th April 2015 at 06:21 PM.

  2. #12
    Automated Home Legend Karam's Avatar
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    Well I would imagine that the RS232 or Ethernet ASCII interfaces should be accessible via Cortex API. Probably Ethernet being easiest in the sense of not needing to connect to a serial port.

  3. #13
    Automated Home Ninja marcuslee's Avatar
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    Quote Originally Posted by Karam View Post
    Well I would imagine that the RS232 or Ethernet ASCII interfaces should be accessible via Cortex API. Probably Ethernet being easiest in the sense of not needing to connect to a serial port.
    Thanks for reply Karam.

    So investigating further, it seems to be panning out that:
    - A/Cs based on outdoor unit linked to indoor distribution wall mounted units (like most people are aware of in domestic situations), basically is fairly rudimentary in so far as you buy a box that plugs into each individual wall mounted unit for the cost of ~150. This unit plugs into a special 4 head connector on the wall unit. You set a unique address with DIP switches on the box, then you communicate with each of these boxes via 3 wire RS-485 running MODBUS protocol.
    - RealTime controls caters to this

    - then you go up a step to ones which talk about VRV units which effectively are hotel style/commercial style setups as most people would know them by. So outdoor unit more or less the same, but they start getting to really big sizes, and the indoor units are the concealed into ceiling ones, such that you only see the louvred vents. The difference here is that now all the units talk over 2 wire proprietary buses (in this case for instance Daikin call it DIII Net). So then you have more sophisticated boxes which then bridge between the two ~2100, but control multiple units (ie we're talking up to 64 or something I think it was)
    - CoolMasterNet supports this

    And the reason for the RS-485 Modbus being so common is (sorry if this is common knowledge), is it seems that's the defacto standard for BMS systems.


    Thanks for reply Karam on the Cortex API - I suspected/knew there would be a way, but knew it was going to be something off piste for my rudimentary use of Idratek.


    Also FYI Video on this page is quite comical - not sure I get quite that level of thrill when using my HA?? :-D
    Also though I missed it on my first watch of the video but at 2:01, there's a quick snippet of where they've housed their HA equipment - I'd never have picked putting it there myself:
    http://www.coolmasternet.co.uk/
    Last edited by marcuslee; 8th April 2015 at 11:08 AM.

  4. #14
    Automated Home Legend chris_j_hunter's Avatar
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    interesting video - their idea of HA, though, seems to go no further than linking things to a smart remote controller / tablet by which the user can interfere in simple ways, the systems being all very separate & stand-alone ...

    wonder if going off-piste would be so bad - makes us nervous, too, but using the API might not be so difficult, albeit what language to use seems to be a difficult thing to get to the bottom of - needs to be simple, and current, MS Visual Studio Express / VisualBasic seems an obvious choice, ‘though a bit of digging shows there seem to be problems when it comes to RS232 ...

    Chris

    http://en.wikipedia.org/wiki/Microso...Studio_Express

    http://en.wikipedia.org/wiki/Visual_Basic_.NET

    https://msdn.microsoft.com/en-us/library/7ya7y41k.aspx

    http://www.innovatic.dk/knowledg/Ser.../SerialCOM.htm

  5. #15
    Automated Home Ninja marcuslee's Avatar
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    Quote Originally Posted by chris_j_hunter View Post
    interesting video - their idea of HA, though, seems to go no further than linking things to a smart remote controller / tablet by which the user can interfere in simple ways, the systems being all very separate & stand-alone ...

    wonder if going off-piste would be so bad - makes us nervous, too, but using the API might not be so difficult, albeit what language to use seems to be a difficult thing to get to the bottom of - needs to be simple, and current, MS Visual Studio Express / VisualBasic seems an obvious choice, ‘though a bit of digging shows there seem to be problems when it comes to RS232 ...

    Chris

    http://en.wikipedia.org/wiki/Microso...Studio_Express

    http://en.wikipedia.org/wiki/Visual_Basic_.NET

    https://msdn.microsoft.com/en-us/library/7ya7y41k.aspx

    http://www.innovatic.dk/knowledg/Ser.../SerialCOM.htm
    Thanks for the links Chris. I suspect on my behalf, due to lack of time, this is only going to go as far as running the cabling in parallel with the a/c units, for a future date to tackle bringing this into Cortex.

    But will see.

  6. #16
    Automated Home Ninja marcuslee's Avatar
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    Quote Originally Posted by Karam View Post
    Well I would imagine that the RS232 or Ethernet ASCII interfaces should be accessible via Cortex API. Probably Ethernet being easiest in the sense of not needing to connect to a serial port.
    Karam, or any others who have coded with CortexAPI (?), if one was to then use ASCII over Ethernet, and using CortexAPI as an interface, as this is beyond my realm of knowledge, what would happen on the Cortex side? ie when configuring the HVAC object, one can see the connection for a Cooling Zone valve... but would the CortexAPI coding allow the AC unit it to appear as this necessary valve?

    And getting beyond this, would there be any ability to provide the user to go via Cortex to set the fan speed of AC unit [low, high, very high]?

    Or for instance the ability to pull from Cortex the set point temp, and then retransmit that to the AC unit (eg to be able to override whatever the unit's remote might have been set the AC unit to)?

  7. #17
    Automated Home Legend chris_j_hunter's Avatar
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    Marcus - not sure we understand the questions (this & the other thread) ! Apart from maybe the fan-speed one ... for that, our units have connections for a simple old fashioned off-board wall-mounted hygrometer (bi-metal strip or some such), for speeding the fan if humidity goes high, and we’ve wired a relay across the terminals of the terminal block by which it’s connected to the circuit board, so Cortex can ask for the same, too ...

    Chris
    Last edited by chris_j_hunter; 11th April 2015 at 11:02 AM.

  8. #18
    Automated Home Legend Karam's Avatar
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    Marcus,

    I'm not an expert on it but as a quick response: I imagine you'd set up your HVAC object as usual and then perhaps connect the zone valve signal to a virtual zone valve. In the API the state of the virtual zone valve will be seen and this can then be translated to some command to be transmitted over ethernet to the AC unit e.g to demand heating/cooling. Similarly I can't see why you can't intercept button presses from a module connected to Cortex (i.e such that the button state changes are transmitted through the API) and then translate these to the AC unit. Should be quite easy. Again the setpoint value of a Cortex HVAC (either cooling or heating) can be interrogated through the API (though I would also imagine it is actively sent whenever a change occurs) so you'd just strip up the value and then send it in an appropriate way to the AC unit (assuming the latter has this facility).

    Just to give you a flavour here is how you would request an HVAC heating setpoint and the kind of response you would get. In this example I'm interrogating an HVAC unit in my Cortex called HVAC1:

    API< HVAC1.Heating Setpoint (output)=?
    WinAPI>
    HVAC1.Heating Setpoint (Output)=23.75

    So, "HVAC1.Heating Setpoint (output)=?" is the message I sent to Cortex via the API (which uses windows messaging system to get the string to Cortex) and then "HVAC1.Heating Setpoint (Output)=23.75" is what I got back from Cortex, telling me that the setpoint is presently 23.75C. In this case I interrogated Cortex but Cortex would send messages without interrogation on state changes for enabled objects. In other words you wouldn't need to constantly interrogate a button state or even the set point but rather you'd have your program act upon any incoming messages, i.e event driven.

    At present the messaging is conducted via the Windows messaging structure and there is a choice of two syntax types. Being simple minded I used the simple API syntax in the example above. To be honest the part I personally struggled most with is getting my head around Windows messaging when trying to implement my code in a different language to those for which we already provide the necessary subroutine exampes (see API help). On the other hand on the horizon is likely to be a web based API i.e of the form where you interact with Cortex via URL encoded messages. This is more suited for people who wish to interact over an ethernet connection directly and with syntax and concepts more in line with the world of IoT (whatever that is :-) ). Nomencelature such as REST and JSON etc. Don't know how many more ways we'll find to skin a cat ....

  9. #19
    Automated Home Ninja marcuslee's Avatar
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    Thanks for replies Chris, Karam. Indeed Karam that was what I was wondering about.

  10. #20
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    The main deiffrence between RealTime products and CoolAutomation's CoolMaster is the number of supported indoor units. CoolMaster supports up to 64 (optionally 128 indoors), while for Realtek, a device required fro each indoor units.
    Theintegration is also simpler : just plug & play.....

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