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Thread: 1st time with FHEM - Questions

  1. #1
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    Default 1st time with FHEM - Questions

    Hi guys,

    I've finally got my CUL device, and installed FHEM on my Debian server and have a couple of initial questions.

    My FHT-80b control unit is connected to a pair of radiator valves (not on the radiator yet, but minor detail). They all have the same code, lets say 1111

    I am following the instructions from the FHEM website, so created the CUL device with code 1234. FHEM automatically found the control unit with code 2222 and was instantly able to read the values, and update it.

    How come this has happened with different codes? I thought the point of the codes was to be secure which this is not.

    I can set the desired temperature from FHEM; however this takes several minutes to be displayed on the control unit display - is this normal / expected?

    If I watch the logs, I can see FHEM receiving information from the control unit (such as measured-temperature, battery ...) this seems to be once every 10-15 minutes - is there a way to make this more frequently. Actuator value seems to be transmitted every 2 minutes.

    Aside from adding all the control units to FHEM, does anyone have any suggestions for what should be setup, or better web frontends?

    Cheers,
    -Jeff

  2. #2
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    Not sure about the CUL devices as I don't have one but as for your other comments, yes, this seems about right. The devices only transmit periodically. The reason for this is twofold, firstly it tries to keep the air waves as clear as possible and because constant transmission would kill the batteries in double quick time.

    As for front ends, there are various options available within FHEM, but I chose to write my own (which currently needs work as I have managed to kill it!)

  3. #3
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    Hi Pheonix,

    Quote Originally Posted by phoenix View Post
    I am following the instructions from the FHEM website, so created the CUL device with code 1234. FHEM automatically found the control unit with code 2222 and was instantly able to read the values, and update it.

    How come this has happened with different codes? I thought the point of the codes was to be secure which this is not.
    I was surprised at this as well - the devices broadcast their addresses, so they ARE discoverable. However allegedly they'll only talk to one device at a time, so as soon as you've bound to them with your CUL device they're supposed to be invisible to to other devices, so this should be secure. I've not proven this, but it's what I've been told on here before.

    Quote Originally Posted by phoenix View Post
    I can set the desired temperature from FHEM; however this takes several minutes to be displayed on the control unit display - is this normal / expected?
    This is normal - the devices update every 2 minutes at best, so in an ideal situation you'd send a message seconds before this update, and the update appears more or less instantly. In some cases though the devices can take up to 10 mins to update (from what I've read). In most cases, it's a minute or two.

    Quote Originally Posted by phoenix View Post
    If I watch the logs, I can see FHEM receiving information from the control unit (such as measured-temperature, battery ...) this seems to be once every 10-15 minutes - is there a way to make this more frequently. Actuator value seems to be transmitted every 2 minutes.
    If you can find a way to make this more accurate, I'd be massively happy to hear - from what I've read there's no way to force this, and it's pretty hit-and-miss. I've got some devices that I've seen broadcasting temp every 10 mins, I've seen some devices not broadcast a temperature for over an hour. I suspect there's some algorithm that only broadcasts the temp if it changes significantly, or based on some other criteria.

    Quote Originally Posted by phoenix View Post
    Aside from adding all the control units to FHEM, does anyone have any suggestions for what should be setup, or better web frontends?
    I am (slowly) working on a .Net frontend, but I suspect with your Debian setup this isn't much use to you! So unfortunately I've not had any experience with the other front ends.

    Hope that helps anyhow,

    Russ

  4. #4
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    Thanks for the replies guys.

    Quote Originally Posted by russell_allen View Post
    I was surprised at this as well - the devices broadcast their addresses, so they ARE discoverable. However allegedly they'll only talk to one device at a time, so as soon as you've bound to them with your CUL device they're supposed to be invisible to to other devices, so this should be secure. I've not proven this, but it's what I've been told on here before.
    I've done some tests; the first time the control unit is powered on it will respond to the first CUL device that talks to it. After that, another CUL device can only read the valve %, but not other details (and can't write to it either).

    I've finally got a date for someone to install the TRVs on our radiators so fingers crossed I can have it actually up and running soon

  5. #5
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    Incidentally, if it's any help, I think all of our TRVs that we fitted were Drayton RT212s, which worked fine with the FHT stuff:

    http://www.draytoncontrols.co.uk/RT2...atorValve.aspx

    Russ

  6. #6
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    Quote Originally Posted by russell_allen View Post
    Incidentally, if it's any help, I think all of our TRVs that we fitted were Drayton RT212s, which worked fine with the FHT stuff:

    http://www.draytoncontrols.co.uk/RT2...atorValve.aspx

    Russ
    Thanks,

    I'm going for the honeywell VT117e.

    -Jeff

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