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