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mbus A429 Discriminate SDI For Label.vi


Description

The mbus A429 Discriminate SDI For Label function is useful to treat incoming messages using the same label but different Source-Destination Identifiers (SDI) as separate messages. SDI discrimination is enabled or disabled for one label.

The SDI is the two Least Significant Bits of the data. It serves as a label extension and can help differentiate two identical units in the same environment.

A data stream may include message showing up with different SDIs. In the general case, in sampling, SDI discrimination is disabled, and labels are the only message ID. Therefore, each label is returned individually, regardless of the SDI. When SDI discrimination is enabled, the label-SDI pair is the message ID. In this case, each label-SDI is returned individually.

Example:
Assuming label 001 shows with SDI 0 every 100 ms and with SDI 1 every 100 ms with a 50 ms offset.
Tables below reflect what can be read by the user depending on selected settings.

Queuing  
Label 001 SDI 0 Received at time tag 0 ms
Label 001 SDI 1 Received at time tag 50 ms
Label 001 SDI 0 Received at time tag 100 ms
Label 001 SDI 1 Received at time tag 150 ms
Label 001 SDI 0 Received at time tag 200 ms
Label 001 SDI 1 Received at time tag 250 ms
etc. etc.
Sampling with no SDI filtering
Label 001 Receiving rate of 50 ms
Sampling with SDI filtering  
Label 001 SDI 0 Receiving rate of 100 ms
Label 001 SDI 1 Receiving rate of 100 ms


Parameters  
error in in error conditions that occur before entering the function
portHandle in reference to the configured port
label in ARINC 429 label onto which SDI discrimination is set
enable in Enables (true) or disables (false) SDI discrimination
portHandle out reference to the configured port
error out out error information
function return out function execution status


Handle parameters are available as input and output. Output is a copy of the input and may be used to daisy chain successive VIs and reduce wire density.

Availability

Available in Multibus VI 1.1 and later.

See Also

mbus A429 Discriminate SDI For All Labels.vi

Example

A429 Schedule Label-SDI.vi