BACnetStack_SendSubscribeCOVPropertyMultiple

bool BACnetStack_SendSubscribeCOVPropertyMultiple(
  uint8_t * sentInvokeId,
  const uint32_t subscriberProcessIdentifier,
  const bool issueConfirmedNotifications,
  const bool useLifetime,
  const uint32_t lifetime,
  const bool useMaxNotificationDelay,
  const uint32_t maxNotificationDelay,
  const void * references,
  const uint32_t referenceCount,
  const uint32_t referencesLength,
  const uint8_t * connectionString,
  const uint8_t connectionStringLength,
  const uint32_t networkPortInstance,
  const uint16_t destinationNetwork,
  const uint8_t * destinationAddress,
  const uint8_t destinationAddressLength);

Sends a SubscribeCOVPropertyMultiple request, which subscribes to change-of-value on several properties in one request.

SubscribeCOVPropertyMultiple is a confirmed service (135-2024 clause 13.16). references is referenceCount packed elements, little-endian, each a FIXED 19 BYTES:

*   +-[0]---------*-[1][2]-------------*-[3..6]-------------------*-[7..10]-------------*-[11..14]------------*-[15..18]----------*
*   | uint8 flags | uint16 objectType  | uint32 objectInstance    | uint32 propertyId   | uint32 arrayIndex   | float covIncrement |
*   +-------------*--------------------*--------------------------*---------------------*---------------------*--------------------*
*

flags: bit0 = usePropertyArrayIndex, bit1 = useCovIncrement, bit2 = timestamped. References sharing a monitored object-identifier are grouped into one per-object specification. referencesLength is the total byte length of references (>= referenceCount * 19). Use the language adapter’s packer to build the buffer.

referencesLength must be at least referenceCount * 19; a shorter buffer is DETECTED and rejected rather than over-read. referenceCount must be at least 1, so the cancellation form (an empty subscription list) cannot be sent through this export.

Worked example - subscribe to Analog Input 1’s Present_Value with a COV increment of 1.0, no array index:

*     02   00 00   01 00 00 00   55 00 00 00   00 00 00 00   00 00 80 3F      (19 bytes total)
*     |fl| |objType||objInstance||propertyId  ||arrayIndex  ||covIncrement 1.0f as IEEE-754 LE|
*

referenceCount = 1, referencesLength = 19. flags = 0x02 (bit1 useCovIncrement set; bit0 usePropertyArrayIndex and bit2 timestamped both clear).

Note

Requires the STACK_OPTION_DS_COVM_SUBSCRIBE_COV_PROPERTY_MULTIPLE (with STACK_OPTION_DS_COV_SUBSCRIBE_COV) build option (it turns on STACK_OPTION_SUBSCRIBE_COV_PROPERTY_MULTIPLE, the macro this function checks).

See also: Client response hooks

BACnet reference: ANSI/ASHRAE 135-2024 clause 13.16 (SubscribeCOVPropertyMultiple Service).

Parameters

Parameter	Direction	Description
sentInvokeId	out	The invoke-id of the sent request, valid only if this function returns true.
subscriberProcessIdentifier	in	The process identifier the subscriber uses to distinguish its own subscriptions.
issueConfirmedNotifications	in	Whether to request confirmed (true) or unconfirmed (false) COV notifications.
useLifetime, lifetime	in	If useLifetime is true, the requested subscription lifetime in seconds; otherwise indefinite.
useMaxNotificationDelay, maxNotificationDelay	in	If useMaxNotificationDelay is true, the maximum delay the subscriber accepts before an initial notification.
references, referenceCount, referencesLength	in	The packed COV-reference array described above.
connectionString, connectionStringLength	in	The datalink address to send TO (the destination) - not the local address to send from. For IPv4 this is 6 bytes: 4 octets of IPv4 address followed by 2 octets of port, big-endian (e.g. 0xC0,0xA8,0x01,0x05,0xBA,0xC0 = 192.168.1.5:47808; see BACnetStack_SendRegisterForeignDevice() for a worked example); on BACnet/IPv4 the stack refuses to send to a connection string of any other length, except that a broadcast from a device registered as a foreign device goes to its BBMD and does not use the connection string. MS/TP and BACnet/SC use a different connection-string shape; see their respective Set/Send exports.
networkPortInstance	in	The Network Port object instance to send the message on, or BACNET_NETWORK_PORT_DEFAULT (4194303) for the default/single port.
destinationNetwork, destinationAddress, destinationAddressLength	in	The destination to send the request to.

Returns

True on success, false on invalid parameters or if not compiled.

Topic: Client requests. Declared in CASBACnetStackDLL.h.