Thanks to the modbus implementor(s). Being new to Home Assistant, I struggled with my modbus devices.
I found that the implementation is a bit limited. Modbus devices that are not organized in a logical way can not be supported easily.
Sometimes reading and writing of a register has different meaning for the bits written.
Situation:
A device a 1 register to read the status (status_register with state_closed: 0 / state_open: 1) and another register to control the action.
This can be controlled using ‘covers’.
However, the action is not the same as the status (0 or 1) so a command_on: 1 and command_off: 1 would be needed.
(The device allows a toggle, when a ‘1’ is written).
Modbus Sensors and covers have a name, which must comply to the general name rules, but does not support friendly_name as other platforms do.
For Modbus sensors and covers the register_type can be holding or input. Missing from the code is ‘discrete_input’. It is defined, to be used( CALL_TYPE_DISCRETE = “discrete_input” ), but not implemented.
It would be great to have the different platforms all support the same set of keywords if possible (this is a general remark).