Python errors

The exceptions methods raise. The Python reference lists every group. Each page opens with its main classes, then the other classes, the dictionaries (TypedDict) and the type aliases, in stub order.

BacnetError

class BacnetError(Exception)

Base exception for all BACnet errors.

BacnetProtocolError

class BacnetProtocolError(BacnetError)

Raised on BACnet protocol-level errors (Error PDU).

Some services answer with a structured error body that adds fields to the class and code. Each such attribute is None unless the device’s error carried it.

Attributes: error_class: The BACnet error class, an ErrorClass member (an int equal to the wire value, #1816). error_code: The BACnet error code, an ErrorCode member. first_failed_element_number: For an AddListElement or RemoveListElement ChangeList-Error, or a CreateObject-Error, the position (from 1) of the list element or initial value that failed, or 0 when the request failed for another reason. A server’s write_property_local of a list whose object refuses one element sets it to that element’s position in the list written. first_failed_write_attempt: For a WritePropertyMultiple-Error, the object, property and index of the first write that failed. first_failed_subscription: For a SubscribeCOVPropertyMultiple-Error about one COV reference, its object, property and index. None for a general failure of the request. vendor_id: For a ConfirmedPrivateTransfer-Error, the vendor of the private service. service_number: For a ConfirmedPrivateTransfer-Error, the private service number. error_parameters: For a ConfirmedPrivateTransfer-Error, the encoded vendor-defined error parameters, when the device sent any. vt_session_identifiers: For a VT-Close error that lists them, the local identifiers of the VT sessions that could not be closed.

Attributes:

error_class: ErrorClass
error_code: ErrorCode
first_failed_element_number: Optional[int]
first_failed_write_attempt: Optional[ObjectPropertyReference]
first_failed_subscription: Optional[ObjectPropertyReference]
vendor_id: Optional[int]
service_number: Optional[int]
error_parameters: Optional[bytes]
vt_session_identifiers: Optional[list[int]]

BacnetTimeoutError

class BacnetTimeoutError(BacnetError)

Raised when a BACnet operation times out.

BacnetRejectError

class BacnetRejectError(BacnetError)

Raised when a BACnet request is rejected.

Attributes: reason: The reject reason, a RejectReason member (an int equal to the wire value, #1816).

Attributes:

reason: RejectReason

BacnetAbortError

class BacnetAbortError(BacnetError)

Raised when a BACnet transaction is aborted.

Attributes: reason: The abort reason, an AbortReason member (an int equal to the wire value, #1816).

Attributes:

reason: AbortReason

BacnetLogNotAdvancingError

class BacnetLogNotAdvancingError(BacnetError)

Raised when a paged log read can’t advance (#1530).

The device answered a page by sequence number with records from before the one asked for, as bacnet-stack 1.6.1 does past its sequence wrap, or with none where its record counts say it holds that record. Read the log by position instead.

Attributes: requested: The sequence number asked for. returned: What the device numbered the first record it sent; None when it sent none.

Attributes:

requested: int
returned: int | None

BacnetReadRangeViolationError

class BacnetReadRangeViolationError(BacnetError)

Raised when a strict read_range refuses an answer that breaks a ReadRange rule (#1531). Read again with validation="lenient" to keep the answer and the rules it broke.

Attributes: rule: The rule broken, in snake case, such as "zero_first_sequence_number".

Attributes:

rule: str

BacnetBvlcNakError

class BacnetBvlcNakError(BacnetError)

Raised when a BBMD answers a management request (read_bdt and its siblings, #1841) with a BVLC-Result NAK. No reply raises BacnetTimeoutError instead, so a refusal and silence never share a class.

Attributes: result_code: The BVLC result code it sent, such as 0x0010 (Write-BDT refused), 0x0030 (registration refused) or 0x0050 (delete refused).

Attributes:

result_code: int

BacnetBvlcUnexpectedResponseError

class BacnetBvlcUnexpectedResponseError(BacnetError)

Raised when a management request (read_bdt and its siblings, #1841) is answered by a BVLC message it doesn’t take, such as a success result to a table read.

Attributes: expected: The BVLC function code the request takes as its answer. got: The BVLC function code that came.

Attributes:

expected: int
got: int

BacnetTransportError

class BacnetTransportError(BacnetError, OSError)

Raised when a transport socket or I/O operation fails.

Covers a failed bind or listen (B/IP, B/IPv6, ScHub.start), a refused or failed dial, and other socket errors. It is also an OSError: errno is the operating system’s code when it reported one, else the code for the failure’s kind (for example errno.EADDRINUSE), else None; strerror is the message. except OSError and except BacnetError both catch it. Unlike a bare OSError it is not narrowed to ConnectionRefusedError and the like, so test errno.

Attributes:

errno: int | None
strerror: str | None
sc_untrusted_peer: ScUntrustedPeerInfo | None: Untrusted certificate evidence from the actual failed outbound TLS attempt. None when unavailable at the verification observation point. This is not an authenticated peer or a history of background reconnect failures.

BacnetRouterCloseError

class BacnetRouterCloseError(BacnetError)

A settled cleanup failure. The router retains it and prevents restart.

Attributes:

failures: tuple[RouterCleanupFailure, ...]

ObjectPropertyReference

class ObjectPropertyReference(TypedDict)

The object, property and array index a structured error names.

Keys:

object_identifier: ObjectIdentifier
property_identifier: PropertyIdentifier
property_array_index: int | None

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