Support dual polling groups for critical and non-critical measurements

[ssander96]

Describe the current behavior
Currently, all Modbus sensors are polled at the same interval. This results in unnecessary load on the Modbus interface, especially for less critical measurements like voltage and frequency.

What should be updated or changed?
It would be useful to introduce support for two polling groups:

A high-priority group for important measurements like power, current, and energy.

A low-priority group for less critical data like voltage, frequency, and temperature.

Each group should have its own configurable scan_interval, so that the system can poll important data more frequently without overloading the Modbus device.

Home Assistant (please complete the following information):

Home Assistant Core Version: 2025.7.1

solaredge-modbus-multi Version: 3.1.4

Additional context
This feature would help reduce Modbus traffic, improve responsiveness for critical sensors, and avoid timeouts or dropped responses caused by over-polling the SolarEdge inverter.

[WillCodeForCats]

Home Assistant can only support a single polling interval for its update coordinator.

Device groups are already performed in single requests of up to 256 bytes per read to minimize the number of requests as much as possible with the addressing scheme and option groups: it IS NOT a read per sensor, sensors are grouped into single read requests. Right now with all possible options enabled there is a maximum of 12 reads per polling interval, with largest increase in read groups coming from power control options.

Inverter only is a single read request (plus another request for version to dynamically catch firmware updates). All meter sensors are a single read request. All battery sensors are a single read request. So with power control options ans extra sensor options disabled you can have as few as 4 or 5 read requests per polling interval per inverter device group.

I would need hard evidence that adding more read requests solves a problem, but this is not really something I see myself spending time on.