Comfort Home Automation/ Security System Forums Home
Home Search search Menu menu Not logged in - Login | Register

Reading values back from Comfort
 Moderated by: admin
 New Topic   Reply   Printer Friendly 
 Rate Topic 
AuthorPost
 Posted: Tuesday Apr 19th, 2011 07:22 am
   PM  Quote  Reply 
1st Post
Glouba
Member
 

Joined: Tuesday Apr 19th, 2011
Location:  
Posts: 15
Status: 
Offline

  back to top

Hello cytech community.

First of all, sorry if this question is too basic. I'm quite new to comfort and KNX so please forgive me.
I'm trying to interact with comfort through KNX. The "KNX to Comfort" part seems to work fine (I can arm the system, etc.) but I have a question about the "Comfort to KNX" part.

The events are successfully sent to the KNX bus (in case of alarm, etc.), but I don't understand how I can get these statuses on demand.
When trying (with ETS) to "read" from the group address assigned to a "Comfort to KNX" value, for example the "Line Cut State", I'm not able to get the value back.

I would like to know if this mechanism is only trigger based, or if it is possible to read the value anytime I want (which seems to be useful, but I may not be catching the whole KNX philosophy) ?
Or at least be able to re-trigger the events such as when comfort starts up (and send all zone values to KNX).

I'm using a Gira HomeServer so maybe it is its task to store the statuses from Comfort, and update the internally stored values when comfort triggers an update ?
But what about the case where the HomeServer is down (power outage for example) and gets powered back on. It should be able to read back the values from Comfort to get in sync with the statuses.
How can I do that ? Is there something easy I am missing ?

Thanks for your help, and again sorry if my question is too dumb :)



 Posted: Tuesday Apr 19th, 2011 09:11 am
   PM  Quote  Reply 
2nd Post
ident
Administrator


Joined: Wednesday Aug 9th, 2006
Location: Singapore
Posts: 3495
Status: 
Offline

  back to top

Reading the values on the Comfort group addresses from KNX is not supported at the moment, although it is being considered for the future

Comfort always reports the zones and events as they occur so your Homeserver should kepp track of these
If your Homeserver is reset or joins the network later you can reset the UCM/KNX to get UCM/KNX  to send its initial values
Otherwise you can program a KNX button to map to a Response which does a system Reset of Comfort



 Posted: Tuesday Apr 19th, 2011 11:00 am
   PM  Quote  Reply 
3rd Post
Glouba
Member
 

Joined: Tuesday Apr 19th, 2011
Location:  
Posts: 15
Status: 
Offline

  back to top

Thanks for your fast answer !

Reading values directly from comfort would indeed be -in my opinion- a nice feature to have. I'm looking forward to get an updated version of the UCM/KNX firmware supporting that.

In the mean time, triggering a reset of the UCM/KNX could also do the trick.
But I guess it is not possible to reset the UCM/KNX through KNX directly ?

And resetting the whole comfort system through KNX seems dangerous : if the HomeServer enters or gets powered as an alarm state is occuring, then this alarm state would be reset. I definitely do not want that to happen! Any idea ?

As it is quite unlikely that the HomeServer could be offline, I'll probably start by keeping the values in the HS and having them updated when Comfort triggers updates. This seems indeed to be the best solution in the current state of the firmware.

So, is there a way to reset only the UCM/KNX through KNX ?
Again, reading the values from the UCM would be a very nice feature !

Thanks again.



 Posted: Tuesday Apr 19th, 2011 02:02 pm
   PM  Quote  Reply 
4th Post
ident
Administrator


Joined: Wednesday Aug 9th, 2006
Location: Singapore
Posts: 3495
Status: 
Offline

  back to top

I was also looking for a way to reset the UCM/KNX through KNX but there is no such action code at the moment, only a global reset is available.



 Posted: Tuesday Apr 19th, 2011 02:05 pm
   PM  Quote  Reply 
5th Post
Glouba
Member
 

Joined: Tuesday Apr 19th, 2011
Location:  
Posts: 15
Status: 
Offline

  back to top

Well, that could be another feature to implement in the next firmware release :)



 Posted: Wednesday Apr 20th, 2011 11:55 am
   PM  Quote  Reply 
6th Post
Glouba
Member
 

Joined: Tuesday Apr 19th, 2011
Location:  
Posts: 15
Status: 
Offline

  back to top

I was thinking again about this "re-trigger KNX events" feature...
Without any new development, wouldn't it be possible to assign the UCM/KNX events (Comfort to KNX) to comfort counters values (KNX to confort... kind of a loopback), then assign a new group adress to a response that would trigger multiple actions : send each "KNX" counter value to the KNX group address.

So the idea is to store the UCM/KNX value in a comfort counter (instead of HomeServer vars), and be able to send a specific event to comfort that would trigger all counters to be sent to KNX.

For example : The line cut state.
We could say that this UCM/KNX event is sent to the 1/1/1 KNX group address (Comfort to KNX).
Then we also say that te 1/1/1 group address (KNX to comfort) value is stored in counter001. (loopback to store the value, but could also be used in read only by the KNX devices)
Then we also create a new response (from KNX group address 2/1/1) that would trigger the action to send the counter001 value to group address 1/1/1. (= re-trigger)

If that is possible, we would keep the same behavior with events, with the ability to send back all events on demand without resetting comfort.

Also, I don't know if it is possible to send the counter value to KNX (didn't see the option in comfort, but had just a quick look), it seems that KNX actions are only made for sending static values.
But as most counters values are just binary, we could simply use an action that sends 1 to KNX if counter equals 1, and 0 if counter equals 0.

Does this seem possible/logical to you ? Or am I totally wrong ?
Just a thought anyway...

Thanks to let me know :)



 Posted: Wednesday Apr 20th, 2011 12:27 pm
   PM  Quote  Reply 
7th Post
ident
Administrator


Joined: Wednesday Aug 9th, 2006
Location: Singapore
Posts: 3495
Status: 
Offline

  back to top

a KNX Group Address can only appear once in the Comfort to KNX and KNX to Comfort Tables. Hence if 1/1/1 is mapped to Line Cut state in Comfort to KNX, then you will not be able to enter 1/1/1 again in the KNX to Comfort table mapped to a counter. You will see that the drop-down list  to select group addresses prevents you from selecting addresses that are already in the tables.

I believe that allowing group addesses "belonging" to Comfort for security conditions may not be to difficult to implement so that would be a better solution

On the other question, when a Counter's value changes that change is sent to the KNX group address
For example say 0/0/1 is a 1-bit Group address (EIS1) is mapped to Counter 10
If Counter 10's value is changed to 255, then a telegram to 0/0/1 is sent with value ON.
Changing counters from Comfort does not activate a Counter Response but  changing counters from KNX will activate the Counter Response for that counter




 Posted: Wednesday Apr 20th, 2011 12:50 pm
   PM  Quote  Reply 
8th Post
Glouba
Member
 

Joined: Tuesday Apr 19th, 2011
Location:  
Posts: 15
Status: 
Offline

  back to top

What a fast answer ! :)

Thanks for the clarification about sending the counter state to KNX.
So the loopback "Comfort to KNX" -> "KNX to Comfort" is not possible, thank you for pointing that out too.

So another possibility could be :

1) Keep the UCM/KNX normal configuration and behavior (for example, line cut sends event to KNX 1/1/1 address) - no loopback trick to store values in counters
2) For the desired comfort events, assign the action to update a counter with the event value (i.e. the "line cut" event would update counter001), this is totally independent of KNX
3) Add a "KNX to Comfort" address (2/1/1) that will trigger the sending of all counter values to KNX bus (in my example counter001 value would be sent to 1/1/1)

The "2/1/1 response" will have to send all counters values, one after the other (max 10 messages at the time).

Does that make more sense ?



 Posted: Wednesday Apr 20th, 2011 01:07 pm
   PM  Quote  Reply 
9th Post
ident
Administrator


Joined: Wednesday Aug 9th, 2006
Location: Singapore
Posts: 3495
Status: 
Offline

  back to top

That would be quite laborious to program even if it were possible

an action to reset the UCM/KNX or to be able to read the group address would be miuch easier



 Posted: Wednesday Apr 20th, 2011 01:20 pm
   PM  Quote  Reply 
10th Post
Glouba
Member
 

Joined: Tuesday Apr 19th, 2011
Location:  
Posts: 15
Status: 
Offline

  back to top

Indeed, that would be laborious. We agree :)

Resetting the UCM KNx or being able to read the values is definitely a lot better, but not available at the moment, and we cannot program that by ourselves (do we? :?).

So until an updated firmware is released, the easiest way to go is probably the full system reset.
BUT, would it be possible that this event only triggers the reset IF the system state is "disarmed" (to avoid obvious security issues!) ? Is there an action to check the system state ?



 Posted: Wednesday Apr 20th, 2011 01:32 pm
   PM  Quote  Reply 
11th Post
ident
Administrator


Joined: Wednesday Aug 9th, 2006
Location: Singapore
Posts: 3495
Status: 
Offline

  back to top

Yes you can do
If Security Mode = Off
 then Reset System
Endif

If the system is reset while the security is armed, after reset it will re-arm to the same security mode



 Posted: Wednesday Nov 2nd, 2011 11:44 am
   PM  Quote  Reply 
12th Post
TheMax74
Member


Joined: Monday Jul 16th, 2007
Location: Italy
Posts: 241
Status: 
Offline

  back to top

Hello, i'm interested too in reading comfort zones from Gira homeserver or any other external device.
Maybe you can implement a simple way to re-send all mapped zones (like when you reset comfort) by reserving a mapped group address to do it.



 Posted: Wednesday Nov 2nd, 2011 01:09 pm
   PM  Quote  Reply 
13th Post
ident
Administrator


Joined: Wednesday Aug 9th, 2006
Location: Singapore
Posts: 3495
Status: 
Offline

  back to top

Perhaps there is a way to send a message to reset the UCM/KNX so it can resend the zones



 Posted: Wednesday May 23rd, 2012 07:52 am
   PM  Quote  Reply 
14th Post
ekarak
Member
 

Joined: Wednesday Apr 21st, 2010
Location: Athens, Greece
Posts: 51
Status: 
Offline

  back to top

Hello good people at Cytech!

Regarding the alarm & zone status updates to the KNX bus: it is essential that the UCM/KNX responds to status reads. I've noticed in large installations (>16 zones) that packet drops are possible, thus you cannot be certain if a zone is open or not (so as to show it on a KNX touchpanel). UCM/KNX has to be more frugal regarding the sending of bursts of packets on the KNX bus. Thus, if a KNX screen displays all zones on a floor it could query the bus for the zone status.
Responding to KNX READ request packets shouldn't be too hard to implement (if UCM/KNX has its own CPU and memory, why not?).



 Posted: Wednesday May 23rd, 2012 12:57 pm
   PM  Quote  Reply 
15th Post
ident
Administrator


Joined: Wednesday Aug 9th, 2006
Location: Singapore
Posts: 3495
Status: 
Offline

  back to top

Perhaps it may be possible for the UCM/KNX to respond to read requests from the Bus
However in your example if a KNX screen shows many zones and you query each zone for its status then that is going to cause a lot of traffic on the bus which itself may cause more problems

Our understanding is that KNX has a mechanism to do error correction so should not drop packets  to cause zones status to be incorrect?



 Posted: Wednesday May 23rd, 2012 01:11 pm
   PM  Quote  Reply 
16th Post
ekarak
Member
 

Joined: Wednesday Apr 21st, 2010
Location: Athens, Greece
Posts: 51
Status: 
Offline

  back to top

The KNX standard states: no more than 3 retransmissions for a failed transmit with random back-off delay (not exponential like Ethernet!), so: Yes it's possible for a poorly programmed device that floods the bus to saturate it.

That's the reason why in practice most KNX devices have a "maximum transmissions rate" parameter, typical value set to something like 30 packets / 15 sec., as well as a "wait timeout before reading initial values from the bus" so as touchscreens coming alive after power failure to wait a little before querying e.g. temperature sensors.



 Current time is 01:12 am
Top




UltraBB 1.172 Copyright © 2007-2014 Data 1 Systems