Hi vijay,

It is not clear to me what you mean by 'BACnet point' . BACnet4J by itself doesn't refer to things as points, they are objects with properties. Can you clarify your question?

It sounds like maybe you're trying to use BACnet4J to modify the available objects on the other device?

Hi vijay,

There may be more than one solution, but we have solved this on our MangoES product for instance by using udev rules to create a symlink with a consistent name. In our case, we used the attributes identifying which USB port the device was connected to. You may find this stack exchange thread helpful: https://unix.stackexchange.com/questions/66901/how-to-bind-usb-device-under-a-static-name

You'll need to use udevadm to find the attributes to identify the port by, and then a /etc/udev/rules.d/ rule to SYMLINK+="ttyNewSymlinkName"

Modbus does not provide a built-in way of detecting slaves. So to do what you want to do would need to be a hack or workaround...Such as polling each slave, if there is a response from that slaveId even if it is an error code such as "illegal address", then there is probably a slave of that ID ??

The most proactive thing you could do for the issue of the null pointer is perhaps to fork the repository, implement some tests that use input and output streams, finish the TestSerialPortWrapper class, and submit a pull request.

But, if you're trying to talk to an actual device and not simply playing with the test code, then perhaps you are wanting to use your own implementing class of SerialPortWrapper which presents the input and output streams of your serial port in the methods that return null in the test class.

In Mango, our Modbus module makes a call to the SerialPortManager to get a proxy, and then returns the input stream and output stream from the proxy.

https://github.com/infiniteautomation/ma-core-public/blob/main/Core/src/com/infiniteautomation/mango/io/serial/SerialPortManagerImpl.java#L205
returns
https://github.com/infiniteautomation/ma-core-public/blob/main/Core/src/com/infiniteautomation/mango/io/serial/JsscSerialPortProxy.java
for non-virtual serial ports in Mango, which uses Jssc to actually handle the serial nitty-gritty.

@phildunlap thanks a lot.