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OpAsync 1553 RT Send block




This block is used to prepare data sent by one simulated RT/SA of a MIL-1553 card.

  • This block does dot trigger transmission of this data since transmission of commands is controlled by OpAsync_1553_BC_Send blocks.
  • This block is associated with one MIL-1553 card through the Controller ID parameter, which associates this block with an OpAsync1553_Ctrl block in the model.
  • The information about the RT/SA couple specified in this block is transferred to the Asynchronous Application in order to program the card for simulation of this RT/SA in transmission mode.
  • The data to be sent by this RT/SA couple is transferred from the model to the Asynchronous Application via the shared memory opened during model initialization.

For more information MIL-1533 RT-LAB applications, see the RT-LAB MIL-1553 documentation.


Controller ID

This parameter is used to retrieve to which Op1553_AsyncCtrl block the present block is associated. This ID is a literal integer value in the range [0, 255].

An Op1553_AsyncCtrl block with the same ControllerID value must exist in the model.

Send IDThis parameter is used by the Asynchronous Process to differentiate between the OpAsync_1553_RT_Send blocks attached to the same Op1553_AsyncCtrl block.
Sub-device number

Some MIL-1553 boards can support more than one MIL-1553 device. Each individual device is then referred to as one sub-device.

This parameter is used to associate the current OpAsync_1553_RT_Send block with one sub-device of the MIL-1553 card selected in the associated Op1553_AsyncCtrl (same ControllerID value).

This parameter is grayed out if the card selected in the Op1553_AsyncCtrl block holds only one sub-device.

Remote TerminalIndicates the number of the Remote Terminal simulated by this block. This value is a literal integer value in the range [0, 30].
Sub-AddressIndicates the Sub-Address simulated by this block. This value is a literal integer value in the range [0, 31].
BroadcastIndicates that the current Send block has to be configured to send broadcast messages for a given Sub-Address. The Remote Terminal number is automatically set to 31.
Buffer modeSelect the buffer mode for the current block. This feature is not supported on QPCX cards.
Detect data readWhen this parameter is checked, the RT/SA is programmed so that an internal flag is set in the MIL-1553 driver at the completion of each transmission. This feature is not supported on QPCX cards
'Data ready' management

This parameter manages the use of the 'Data ready' signal. The user has the option of controlling it entirely, allowing a change detection mechanism to control it or a combination of the two.

This is achieved by means of a drop-down menu.

The options are:

  • Block input only: data is sent according to the block input 'Data ready'
  • Block input and data change check: when this option is chosen, the data is sent when the block input is '1' and the change detection mechanism of the block finds a new set of values
  • Data change check only: the 'Data ready' signal is asserted automatically every time a change in the input data is detected; in this case, the block input disappears as the signal assertion is handled entirely by the block
Enable error injectionChecking this box enables the error injection mechanism. For more details see the error injection section. This feature is only available on supported QPCX cards. 


This block has 2 inputs when the error injection checkbox is disabled.

  • Data Ready: this input is used to flag to the Asynchronous Process that new Data can be placed on the card for transmission by the RT/SA.
  • Data: this input specifies the data to be transmitted by the RT/SA, on the MIL-1553 bus

When the error injection checkbox is enabled, additional inputs are present. See the error injection section for more details.


This block has one output used to return values set by the Asynchronous Process.

  • Error: This output reports one of the following values:
0No errors.
-1An error occurred during initialization and the asynchronous process has terminated. Consult the RT-LAB Display for details.
-2An exception occurred. Please contact the Opal-RT support team should this be reported. Consult the RT-LAB Display for details.
-4A transmission error occurred. This may also be the result of an exception.

The previously written data had not been transmitted. This is to be considered as information more than an error.

The data update is performed even if this situation occurs.

Error injection

When the Enable error injection checkbox is enabled the block has these additional inputs.


  • Error injection index: This index is used to select an error injection buffer to be applied. The value of the signal relates to the error injection ID of an OpAsync 1553 Error injection buffer block (EI BUF) . When '0' no error injection buffer will be applied to the data. For more details on how the error injection buffer block can be used to inject errors see the OpAsync 1553 Error injection buffer block documentation.
  • Message error bit: If '0', all command words received by the RT will be considered legal. Otherwise, all command words received are illegal and the RT will answer with the message error bit set to '1', no data word will be transmitted.
  • Busy bit:  This signal allows the user to set or unset the busy bit in the status word. If the busy bit is set, the transmission of the data word will be stopped.

Each of these three entries must be connected to a scalar signal.

Characteristics and Limitations

This block has no special characteristics.

Direct FeedthroughNo
Discrete sample timeNo
XHP supportNo
Work offlineNo

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