Unexpected behavior with NI-9124 Temperature Input Module when enabling Open Thermocouple Detection

[orestes-morales]

Describe the bug

• The custom device won't update or show incorrect values if the NI-9124 Temperature Input Module has opened channels and the Enable Open Thermocouple Detection is activated.
• The problem has been identified in the forum thread Re: Scan Engine & EtherCAT Custom Device Feedback - Page 26 - NI Community.), which mentions that if the custom device finds an open thermocouple channel, all the following channels on that iteration won't be updated

To Reproduce Steps to reproduce the behavior:

1. Enable Open Thermocouple Detection for a NI-9124 Temperature Input Module in Veristand's project System Definition File.
2. Leave at least one thermocouple channel disconnected.
3. Deploy the project and observe that all channels following the disconnected one will not update or show an incorrect number.

Expected behavior

• The expected behavior would be to have an indication that the channel is opened but still observe the correct values for all the other channels.

Screenshots If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: NI Linux RT
• Version 21+

Additional context

• We have found that the issue stems from how the Scanned Variable Read VI, found in the SEECD Engine.lvlib:Scanned Read - Input Model.vi, behaves when a channel error occurs while reading an array of channels altogether.

• A possible fix or workaround consists in reading each of the channels individually, as shown in the image below and attached VI. Scanned Read - Input Module.zip

• The caveat of this workaround is that it increases the time it takes to read all channels compared to reading them altogether, from 0.12 ms to 0.80 ms.