Writing 'null' to a priority in a propertyArray

[trapperl]

I've been working on a BACnet project and have had a lot of luck reading a writing.

However I've hit a roadblock trying to write 'null' so that the values are cleared out of the priority array.

To simplify things, I went back to the write-property-console.py

https://github.com/JoelBender/BACpypes3/blob/main/samples/write-property-console.py

It can't pass a string as a float when I do this, which makes sense:

write 10.102.14.100 analogOutput:0 presentValue null 8

When I see if the value is null and try to pass Null()

if value.lower() == 'null': value = Null()

I get a type error.

write error: | Error type : <class 'TypeError'>

I assume the problem is something I don't know and am having trouble finding.

Any help would be appreciated.

[bbartling]

So I've made this ultimate bapypes3 tester script via the bacpypes console:

https://gist.github.com/bbartling/24d4fa106281a63e7b6a77a2f40fe183

And have played around with some scripts outside of the bacpypes3 console. At least in the console I think you want something like a > write 32:18 analog-output,2 present-value null 10

In a script form you just want pass in a string like "null"...

Hopefully these code snips help but the important part is the:

            if priority is None:
                raise ValueError(" null only for overrides")
            value = Null(())

That is inside the write method:

from bacpypes3.primitivedata import Null

    async def do_write_property_task(
        self,
        device_address,
        object_identifier,
        property_identifier,
        value,
        priority=BACNET_WRITE_PRIORITY,
    ):
        if _debug:
            logging.info(" device_address: %r", device_address)
            logging.info(" object_identifier: %r", object_identifier)

        # Use the parse_property_identifier method to split the property identifier and its index
        property_identifier, property_array_index = self.parse_property_identifier(
            property_identifier
        )

        if _debug:
            logging.info(" property_array_index: %r", property_array_index)

        # Check the priority
        if priority:
            priority = int(priority)
            if (priority < 1) or (priority > 16):
                raise ValueError(f"priority: {priority}")
        if _debug:
            logging.info(" priority: %r", priority)

        if _debug:
            logging.info(" value: %r", value)

        if _debug:
            logging.debug(
                "do_write %r %r %r %r %r",
                device_address,
                object_identifier,
                property_identifier,
                value,
                priority,
            )

        if value == "null":
            if priority is None:
                raise ValueError(" null only for overrides")
            value = Null(())

        try:
            response = await self.app.write_property(
                device_address,
                object_identifier,
                property_identifier,
                value,
                property_array_index,
                priority,
            )
            if _debug:
                logging.info(" response: %r", response)
            if _debug:
                logging.info(" Write property successful")
        except ErrorRejectAbortNack as err:
            if _debug:
                logging.info("    - exception: %r", err)
            else:
                logging.error(" Write property failed: ", err)

    async def do_release_all_hvac(self):
        logging.info(" Releasing all HVAC!")

        write_requests = [
            (
                TRANE_ADDRESS,
                TRANE_TEMP_SETPOINT_READ_WRITE_POINT,
                BACNET_PRESENT_VALUE_PROP_IDENTIFIER,
                "null",
            ),
            (
                TRANE_ADDRESS,
                TRANE_AIR_FLOW_STP_WRITE_POINT,
                BACNET_PRESENT_VALUE_PROP_IDENTIFIER,
                "null",
            ),
            (
                TRANE_ADDRESS,
                TRANE_COOL_VALVE_WRITE_POINT,
                BACNET_PRESENT_VALUE_PROP_IDENTIFIER,
                "null",
            ),
        ]

        for request in write_requests:
            try:
                # Destructure the request into its components
                address, object_id, prop_id, value = request

                # Perform the BACnet write property operation
                await self.do_write_property_task(address, object_id, prop_id, value)
                logging.info(f" Write successful for {object_id}")

            except Exception as e:
                logging.error(f" An unexpected error occurred on WRITE REQUEST: {e}")

[trapperl]

Thanks for your help.

I can't believe I just needed to change Null() into Null(())