Add parameter for serial port name to Modbus RTU interface schema

mkrebs81 commented 2 months ago

I have noticed that the interface schema of Modbus RTU devices contains all serial port connection options, except the actual serial port.

I understand that the reason might be the still hard-coded parameters of most product profiles (EIDs).

However, since we have the configurationList now, I suggest adding the serial port parameter to the XML schema. If the serial port is available, I can

get all necessary parameters directly from the SGr EID
implement cases where multiple serial ports are present

ergo-furrer commented 2 months ago

This is a good point. If I understand correctly, you propose to add something like:

    <modbusInterfaceDescription>
        <modbusInterfaceSelection>RTU</modbusInterfaceSelection>
        <modbusRtu>
          <comPort>{{comPort}}</comPort>
          <slaveAddr>{{slaveAddr}}</slaveAddr>
    ........

and then:

  <configurationList>
    <configurationListElement>
      <name>comPort</name>
      <dataType>
        <string/>
      </dataType>
      ........

We have to keep in mind, that with the current Java CommHandler implementation the communicator needs to instantiate the RTU communication driver separately and the COM port is not needed to be in the EI-XML:

     GenDriverAPI4ModbusRTU mbRTU = new GenDriverAPI4ModbusRTU();
     mbRTU.initTrspService("COM3", 19200);
     var modbusDevice = new SGrModbusDevice(devDesc, mbRTU), null);
    ....

However, with the EI-XML change as suggested above we can change the CommHandler code to automatically load and configure the modbus driver (or in general the communication drivers) depending on the EI-XML content, which is a good thing from my point of view. I will add this to the todo's list within the Java issues.

mkrebs81 commented 2 months ago

Thank you for the feedback. The XML draft is exactly what I had in mind.

However, I would not change the instantiation of the modbus driver, because putting it inside the comm-handler would not allow multiple devices on the same RS485 bus.

As far as I understand, I have to use the same GenDriverAPI4ModbusRTU object when trying to access multiple devices on the same bus.

I am currently working on an "extended" SGrModbusDevice, which uses a shared driver instance and calls setUnitIdentifier() on the transport before calling setVal or getVal.

ergo-furrer commented 2 months ago

As far as I understand, I have to use the same GenDriverAPI4ModbusRTU object when trying to access multiple devices on the same bus. Indeed, I did not think of that. Yes we should keep it as is!

I am currently working on an "extended" SGrModbusDevice, which uses a shared driver instance and calls setUnitIdentifier() on the transport before calling setVal or getVal. Thanks, this sounds good! Tell me if you have the related pull-request ready.

mkrebs81 commented 1 month ago

@ergo-furrer I just noticed that you updated the SGr specifications. Is it correct that all Modbus interface parameters are now returned as strings instead of enums?

One more comment regarding the serial stop bits options: AFAIK, the value 0 is not allowed. only 1, 1.5 and 2.

Also, the ByteLength option cannot be set when initializing the Modbus transport.