Controlling SSM and SDI Values in Ballard ARINC-429 Tx Message

Issue Details

I am using the NI VeriStand Ballard ARINC-429 Custom Device to communicate with my 429 bus. My test requirements state that my HIL tester needs to have the ability to change the Source Destination Identifier (SDI) and Sign Status Matrix (SSM) values in transmitted (Tx) messages to test fault conditions. 

In the custom device, I see that there are "CreateSDIChannel" and "CreateSSMChannel" XML tags for the Parameters XML file that specify whether to create SDI and SSM channels for any configured labels. However, when I try to add these for my Tx labels, I don't see those channels being created in VeriStand.

How can I control the SDI and SSM values from VeriStand for Tx labels?

Solution

The "CreateSDIChannel" and "CreateSSMChannel" tags are only supported for Receive (Rx) messages/labels. If you add those tags for Tx labels in the Parameters XML file, they are ignored and the channels are not created.

However, it is still possible to control the SDI and SSM values. You just have to explicitly create parameters under each label for these values that cover the appropriate bits:

For example, an SDI parameter should be configured like this:

• direction: outgoing
• encoding: BNR
• startBit: 8
• numberOfBits: 2
• scale: 1

An SSM parameter should be configured like this:

• direction: outgoing
• encoding: BNR
• startBit: 29
• numberOfBits: 2
• scale: 1

Here is an example XML for a label showing these two parameters added. The full Parameters.xml file is attached to this article:

<label>
	<labelDecimal>23</labelDecimal>
	<transferType>0</transferType>
	<period>10000</period>
	<parameter>
		<encoding>BNR</encoding>
		<signed>true</signed>
		<startBit>10</startBit>
		<numberOfBits>19</numberOfBits>
		<scale>1.0</scale>
		<offset>0.0</offset>
		<name>23_Parameter 0</name>
		<unit>psi</unit>
		<defaultValue>52.0</defaultValue>
	</parameter>
	<parameter>
		<encoding>BNR</encoding>
		<startBit>29</startBit>
		<numberOfBits>2</numberOfBits>
		<scale>1</scale>
		<offset>0</offset>
		<name>SSM_Override</name>
		<defaultValue>01</defaultValue>
	</parameter>
	<parameter>
		<encoding>BNR</encoding>
		<startBit>8</startBit>
		<numberOfBits>2</numberOfBits>
		<scale>1</scale>
		<offset>0</offset>
		<name>SDI_Override</name>
		<defaultValue>01</defaultValue>
	</parameter>
</label>

After adding those parameters, when you import the parameters XML file in to the Ballard ARINC 429 Custom Device in VeriStand, you will see those two channels are created for that label:

And you can control the SDI and SSM values directly for those labels: