Well, also in the IP Symcon forum, the limit (duty cycle) was discussed, some time ago (http://www.ip-symcon.de/forum/f18/fhz1300-haengt-7986
), triggered by a hang of the FHZ detected by some users (including me).
I did some intensive research on that issue early 2009 when doing range-tests in my house and considering to use FHZ as a repeater for each and every telegram sent to be save from droputs. To get an idea of what to do and where my critical areas were, I first had FHZ sent a telegram again and again moving around with some receivers. Here I detected the problem:
When sending every 2 seconds (initally 1 second but that lead into a system fail quite soon) it failed after somewhat 50 Minutes or so. Reducing it to one telegram each 3 seconds, I did not encounter problems and was able to make range test for some hours.
I asked the ELV technicians and after insisting with my empirical results that their first answer could not be really true (they told me that 40 to 50 telegrams per hour should be a limit), I got the answer that one telegram in sum will occupy some 20-30 ms of time.
Since they need to adress the 1% (limit in total occupation time per sender, there should be roughly 36 seconds of occupied time per sender (which FHZ is) which means, 36.000 ms of sending time per hous. Using the 30ms, per telegram, you will end up with 1.200 per hour which drills down to one telegram every 3 seconds, using 20ms you will end up with one every 2 seconds, which comes quite close to my empirical values.
What I did in the end was to have one global script (IP Symcon) that repeats all telegrams that are critical where I simply add any adress to a list of "to be repeated ones" that had any problems in real life conditions. This in deed limits the ones to be repeated to somewhat 30 - 70% depending on installations and meanwhile, my system is quite reliable!
Since we sometimes have terribly often power outages (up to 30 times a day in heavy rain/wind periods) that result in out of sync situations between reality of the receivers and status in the software, I do repeat any "on" status after power-on that is detected by a TFK. Additionally, at 4:00am I have a "reset" of all devices to be switched off (because that is the reality in 99,99% of all days a year - apart from birthday and other parties.
FS20-System: FHZ Lan & IP-Symcon, ca. 25 Aktoren, 20 Sensoren, alle Handsender, diverse Eigen- und Umbauten
Anbindung an Squeezeserver, Twonky und TVersity sowie Übergang zu EIB steht aus.