Avoid radio collisions during mass operations in HomeMatic

Third party integrations
1

We have built a heating control dashboard for our mid-size company using 31 identical HomeMatic IP thermostat heads distributed over all rooms of our office building. To “orchestrate” thos devices, we use the scheduler-component integration as well as the scheduler-card dashboard “module” from HACS which works like a charm in general.
All thermostat heads are scheduled to increase the room temperature to a certain value at the same time (currently 5:00am) which works correctly for on most days. But we did notice that some of the thermostat heads do not get triggered but stay at the old (lower overnight) temperature as if they did not receive the “turn temperature up” command.
There are no errors in the CCU logged (like unreachable) and it happens only occasionally and appears to be completely random (so no correlation between the signal strength of the “non-triggered” device or anything like that).

As I operate another larger HomeMatic installations privately at my home, I know that radio collisions can occur when multiple radio-controlled HomeMatic devices are being addressed by the CCU at exactly the same time. At home, I use Node-RED to “orchestrate” the devices and implemented a central component where all “traffic” towards HomeMatic devices goes through. This function block enforces event queueing with a rate limit of one command per second over radio.
Without that throttling element in place, I also did end up with some shutters not opening or closing correctly as this is also a “mass operation” that happens to 14 actors at exactly the same time (due to automation via a cosmic timer module).

I did already search the web for this issue in connection with Home Assistant, but wasn’t able to find anything useful. So my question is: How to avoid radio collisions in such cases where I simply want to use a scheduler module and not “get my hands dirty” in low-level programming? I am a bit astonished that there is obviously no “rate control” setting for radio-controlled HomeMatic devices (which are quite a few) in the rather popular homematicip_local integration.
So I guess I am either the only one experiencing this kind of issue with “mass operations” of radio-controlled actors at certain times of the day or that there are other (hopefully easy to implement) ways to achieve the same goal (operate multiple devices at a given time).

Please don’t advice to use Automations in Home Assistant as this won’t work together with the scheduling components I did mention at the beginning of my post. And those schedulers work perfectly fine - it’s just too much (radio) load on HomeMatic at those given time points. But distributing those “low priority” events over a few seconds would definitely not hurt here but likely solve the purely technical issue here…

I am looking forward to any hints.

Best regards,

FNW

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This would be better managed by central “server” device that monitors and controls the individual units.

You say the scheduler works but it is not completely reliable.

Are the units all changing to same temp or some offset of a standard temp?

I would likely use something like a RasPi or ESP that takes the set temp value from HA and manages the temp changes and verifies the result.

The radio collision is not a big deal if you can see unchanged device and have it changed when error occur. Really the device doesn’t need to be central to operation. It could simply monitor changes and verify when they do not occur and make needed change if needed.

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Thanks for the reply - and what you say is naturally true.
But fixing a reliability issue that just exists because too many messages are going out “uncontrolled” (in the means of being thrown “unlimited” at the HomeMatic CCU) in a very short period of time with another device that does “cleanup operations” and needs to be set up and maintained as well does sound more like a workaround than a real solution.
I would prefer to just eliminate radio collisions (or at least drastically reduce the probability of them) and I guess something like a rate limit for radio events in the homematicip_local integration would be the best approach here.
It’s interesting that the problem seems to be pretty rare in the field because I stumbled across it already over five years ago by just setting up time-controlled movements of my shutters.
I assume it might be pretty common to use scheduled events to trigger multiple actors at once.

So to define my question more precisely: I there any possibility to limit the speed of “event message forwarding” between Home Assistant and HomeMatic?
I can hardly believe that nobody else experiences that problem as time-based controlling of devices like home appliances sure should be pretty common.