Sensor state alive monitoring

JJLeuthold

Monitoring a sensor for its "alive"-state is quite an issue in Enocean. Sensors are supposed to send values only if states change and not so often. It is then difficult to see that a sensor has gone out of service, i.e. it no longer sends "false" or "true" but simply nothing. In many cases one may not notice a sensor failure at all, A burglary alarm may be off because there is no burglary but it may not send a response because it has been forcefully destroyed or its battery is dead.

In an effort to monitor my sensors I have come across the p44script command "sensor1.valid".
I have used this command within a sensor evaluator device. And indeed, this seems to work. If one of the window handles no longer sends a value (i.e. if the burglary value no longer contains a "true" or "false" after about an hour) then the sensor1.valid script evaluation delivers a "false". Fine so far.
However, now the question remains as of how can I trigger the sensor evaluator to evaluate its values every now and so often. I can manually execute the evaluator by tipping on the "Save + Check Expression" botton. This delivers the proper values. But I do not find an option to evaluate the evaluator like twice in an hour. In fact, I have no idea if the evaluator will ever be executed at all and what triggers the execution of an evaluator.

Any help to solving this issue would be greatly appreciated.

luz

Sorry for the long answering delay. Somehow the forum software still does not issue notification mails to me - and I was busy these days with a complicated project so not checking the forum manually all the time.

Regarding any kind of polling - one caveat before going into details: one needs to be careful with adding too many regular pollings to a small system like the P44-xx. These can add up and at some point the performance will suffer.

But basically, you can create polling evaluators by using the testlater() or every() functions (see p44script short reference.

So an evaluator that should check something every 5 minutes would have an ON condition like:

every(0:05) & something

In this, every() gets true once every 5 minutes and causes evaluation. When something is also true at that moment, it will trigger the evaluator. (testlater is similar, but more specialized and was added to the evaluator engine much earlier, when the more generic every() would not have been possible yet).

However, to get notified when a sensor turns to the invalid state, all this is not needed, because the value change from a real value to "invalid" state triggers an evaluation anyway.

So an Evaluator with just the following ON condition should do the trick already:

!isvalid(sensor)

Hope this helps!

PS: note that there's an underlying problem in dS itself, as it still does not handle the "invalid" state separately for binary inputs, but treats it as 0. This is the main cause for unexpected results with sensors/inputs in the invalid state.

JJLeuthold

Wow, Most helpful! Thank you!

JJLeuthold

Actually, the !isvalid command works great! This was a pending issue. I am surprised that one can find little about this command. Without an isalive surveillance there is no real saftey.

As a teaser to others my implementation to monitor the state of the windows. The !isvalid triggers the meassge. The isvalid is used to reset the warning.
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Many thanks Luz!