how can i read from bacnet objects programatically instead of in the command line?

[khavernathy]

In the command line I can do things like this:

read 7 analogValue:10 presentValue

But how can I programatically read like this and store to a variable in python? Currently I'm trying like this:

    this_console = BacnetClientConsoleCmd()
    if _debug: _log.debug("    - this_console: %r", this_console)

    # enable sleeping will help with threads
    enable_sleeping()

    _log.debug("running")
    
    present_value = this_console.do_read("read 7 analogValue:10 presentValue")

[rviswanathan-varohm]

Hi,

You can check this example - https://github.com/riptideio/misty/blob/master/samples/polling_bac_client.py

It is a slighly bloated version, but it does the full cycle of getting all the objects and reading them. You might need a small portion of that to read a object.

One of these days , when I get some time, I would have (1) Read program to read a point (2) write program that would write to a point . Both of them would be command line driven as opposed to console.

[JoelBender]

I would really like to have this project moved over to BACpypes3, applications like this and this are far easier to write. Sadly I do not have a test platform.

[rviswanathan-varohm]

Joel,

Thanks for the suggestion. I will work towards moving this to bacpypes3. Those two applications that you pointed out are pretty cool.

At this time, I test it on my Raspi/Macbook using 'socat'. I create a pair of devices as explained here and test it. It works pretty smoothly. But I understand, A real device would give higher confidence level.

[raghavan97]

@JoelBender ,

I made a port of misty to work with bacpypes3 and put it up in a separate repository - https://github.com/raghavan97/misty3

I was able to test with

• discover-devices.py
• discover-objects.py
• mini-device-revisited.py

I ran mini-device-revisited.py on one side of socat pair of devices and on the other side ran discover-objects.py. Worked really well.

The porting of those applications was pretty trivial too. Just change the Application to point to misty3.mstplib.MSTPApplication and use a extended ArgumentParser - MSTPArgumentParser as mentioned here

I took a slightly different route in bacpypes3 port. I have monkey patched the ingress and egress points (process_npdu and confirmation). I dont know if there are corner cases that I am not dealing with. But that is a for a different day.

While testing with socat on the same machine, there was one small change I had to do in bacpypes3 , using the reuse_port=1 here to be able to run multiple bacpypes3 applications on the same machine. You might want to consider adding that in general to help multiple processes on a machine to use bacpypes3.

Thanks.
Raghavan V