Retrieve sensor values from sensors on OpenHab request

[Guillermo Ruffino]

I know that OpenHab can store the last value of a sensor with persistance, but sometimes OH could go down and then sensor value change and then when it comes back it will show an outdated value.
So far a sensor does not change its value, OH will have null / old data, so how should I approach this?
I'd like it to be automatic, but I really don't know if that is a good idea, e.g. OH requesting all values from all sensors that might flood MS network.

I believe one solution could be from the sensor side implementing receive to answer the req message and then...
from OH side have a rule that will (trigger when?) and request a sensor value, do I have to use the "expert mode" of the binding here?
Please advice

[gohan]

just add some code in the nodes that if sensor data hasm't changed after 5 or 10 measurement, it will force the send of the value to make the controller aware that the sensor is still alive. Implementing a receive function on nodes it can be done but not for battery powered ones.

[parachutesj]

either what @gohan said or persist the values in OH