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OpAsync 429 Scheduled Send




  • The blocks OpAsync_429_Scheduled_Send and OpAsync_429_Scheduled_MajorFrame are used to define the periodic scheduled transmission.
  • The blockOpAsync_429_Scheduled_MajorFrame defines the major frame parameters. It defines the period and the channel of scheduled messages.
  • The OpAsync_429_Scheduled_Send blocks define the minor frame parameters. It defines the messages with its scheduled time execution.
  • Several OpAsync_429_Scheduled_Send blocks can be attached to one major frame to describe the content of the message and its sending time.


ControllerIDSee OpAsync429 Controller documentation.
SendIDEach OpAsync 429 Scheduled Send block is assigned a unique SendID to be distinguished among multiple send blocks.
Sub-device numberOne ARINC 429 board can contain more than one independent ARINC 429 capable device. This parameter specifies which sub-device is to be used by the current block. The availability of the sub-devices depends on the ARINC 429 board model that is used.
LabelAvailable only in Legacy mode. The first 8 bits of the ARINC word, known as the Label, identifies the type of information contained in the 32-bit ARINC word. If the value entered exceeds 255, it returns to 0. The SDI can be used along with the Label in the ARINCword, in this case, the SDI value is automatically incorporated with the label value input in this box.
Use SDIAvailable only in Legacy mode. Checking this box enables the2-bits SDI in the ARINC word.
SDIAvailable only in Legacy mode. The SDI is optional and when used, it occupies bits 9 and 10 of the ARINC word. The SDI adds an extension to the ARINC word's Label. ARINC systems are supposed to decode the Label/SDIcombination as a different Label than an ARINC word with the same label and no SDI implementation.

Selection of the Legacy or Advanced operation mode:

  • In Legacy mode, the 19 bits of the data section of the ARINC word are provided on the 'Data' input, theSSM fields are provided by the 'SSM' input, and label and SDI fields are provided by the parameters. Note that the label bits are transmitted in reverse order.
  • In Advanced format, the 32 bits of the ARINC word are provided by the 'Data' input. In that case, there is no inversion of the label bits.
MajorFrame IDSpecifies the major frame identifier of the corresponding OpAsync_429_Scheduled_MajorFrame block.
ScheduledTime (µs)Specifies the time in microseconds (relative to the start of the minor frame) that must expire before the transmit command block is processed.
StartFrameSpecifies the minor frame in which the transmit command block will first be executed.
Repeat RateSpecifies how often to process a transmit command block after the Start Frame parameter is met. (For instance, RepeatRate=2 means that the message will be transmitted every two minor labels).
Use Parity controlControls the parity generation of the transmitted words. If this parameter is checked, the input 'Parity Control' is added to define if the parity is normal (=odd), even or disabled.


Data ReadyThe block updates the write buffer with the input Data when this input is 1.
DataIn Legacy mode, this input provides the 19 bits data field from ARINC word. In Advanced mode, this input provides the complete 32 bits ARINC word, except for the parity bit, which is set by the board.
SSMAvailable only in Legacy mode, this input provides the 2 bits SSM field from the ARINC word.
Parity ControlAvailable only if the parameter 'Parity Control' is checked. This input defines the parity type of the transmitted word, as outlined in the table below.

Input valueDescription
0Even parity.
1Odd parity. This is the normal parity of the board.
2Parity control disabled. In Legacy mode, the parity bit is set to 0. In Advanced mode, the parity bit supplied in the input Data word is transmitted with no modification.


ErrorCurrently unused.

Characteristics and Limitations

Direct FeedthroughYes
Discrete sample timeYes
XHP supportNo
Work offlineNo

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