BACnet.
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This module represents the BACnet Device Communication Control service.
The Device Communication Control service is used to control the communication of a device.
Service Description (ASHRAE 135)
The DeviceCommunicationControl service is used by a client BACnet-user to instruct a remote device to stop initiating and optionally stop responding to all APDUs (except DeviceCommunicationControl or, if supported, ReinitializeDevice) on the communication network or internetwork for a specified duration of time. This service is primarily used by a human operator for diagnostic purposes. A password may be required from the client BACnet-user prior to executing the service. The time duration may be set to "indefinite," meaning communication must be re-enabled by a DeviceCommunicationControl or, if supported, ReinitializeDevice service, not by time.
Service Procedure (ASHRAE 135)
After verifying the validity of the request, including the 'Time Duration' and 'Password' parameters, the responding BACnet-user shall respond with a 'Result(+)' service primitive. If the request is valid and the 'Enable/Disable' parameter is DISABLE, the responding BACnet-user shall discontinue responding to any subsequent messages except DeviceCommunicationControl and, if supported, ReinitializeDevice messages, and shall discontinue initiating messages. If the request is valid and the 'Enable/Disable' parameter is DISABLE_INITIATION, the responding BACnet-user shall discontinue the initiation of messages except for I-Am requests issued in accordance with the Who-Is service procedure. Communication shall be disabled in this manner until either the 'Time Duration' has expired or a valid DeviceCommunicationControl (with 'Enable/Disable' = ENABLE) or, if supported, a valid ReinitializeDevice (with 'Reinitialized State of Device' = WARMSTART or COLDSTART) message is received. If the responding BACnet-user does not have a clock and the 'Time Duration' parameter is not set to "indefinite," the APDU shall be ignored and a 'Result(-)' service primitive shall be issued. If the 'Password' parameter is invalid or absent when a password is required, the APDU shall be ignored and an Error-PDU with 'error class' = SECURITY and 'error code' = PASSWORD_FAILURE shall be issued.
Result(-) Errors (ASHRAE 135)
The 'Result(-)' parameter shall indicate that the service request has failed. The reason for failure shall be specified by the 'Error Type' parameter.
The 'Error Class' and 'Error Code' to be returned for specific situations are as follows:
| Situation | Error Class | Error Code |
|---|---|---|
| The password is invalid or absent when one is required. | SECURITY | PASSWORD_FAILURE |
| The device does not have a clock and the 'Time Duration' parameter is not set to "indefinite". | SERVICES | OPTIONAL_FUNCTIONALITY_NOT_SUPPORTED |
Summary
Functions
Whether the service is of type confirmed or unconfirmed.
Converts the given Confirmed Service Request into a Device Communication Control Service.
Get the service name atom.
Get the Confirmed Service request for the given Device Communication Control Service.
Types
@type t() :: %BACnet.Protocol.Services.DeviceCommunicationControl{ password: String.t() | nil, state: BACnet.Protocol.Constants.enable_disable(), time_duration: BACnet.Protocol.ApplicationTags.unsigned16() | nil }
Parameters for the Device Communication Control service.
Requests a device to enable, disable, or disable for a time its network communication (except for the controlling device). An optional password may be required by the target device.
If time_duration is nil, then the duration is indefinite.
The password can have a maximum length of 20 characters.
Functions
@spec confirmed?() :: true
Whether the service is of type confirmed or unconfirmed.
@spec from_apdu(BACnet.Protocol.APDU.ConfirmedServiceRequest.t()) :: {:ok, t()} | {:error, term()}
Converts the given Confirmed Service Request into a Device Communication Control Service.
@spec get_name() :: atom()
Get the service name atom.
@spec to_apdu(t(), Keyword.t()) :: {:ok, BACnet.Protocol.APDU.ConfirmedServiceRequest.t()} | {:error, term()}
Get the Confirmed Service request for the given Device Communication Control Service.
See the BACnet.Protocol.Services.Protocol function documentation for more information.