Table of Contents
21 Real-Time
DQMH modules are fully supported on all NI Real-Time target platforms, both with and without Embedded UI.
Seeing as modules have a front-panel-related invoke node (FP.Open) in the “Initialize” case of the MHL, you might experience front panels popping up during or after deployment.
You can find more details about these phenomena here: LabVIEW Real-Time Deployment
To avoid these front panels popping up, you can wrap the FP.Open node in a Conditional Disable Structure to keep it from being executed on RT platforms.
Note: Seeing as some RT targets can have Embedded UI enabled, it might not be good enough to exclude the FP-related nodes from running on TARGET_TYPE == RT. We usually add a custom symbol EMBEDDED_UI to the project to have better control over when to run the FP-related code.
DQMH® 5.0 and later
DQMH 5.0 and later supports both Singleton and Cloneable modules in LabVIEW Real Time. DQMH 5.0 modifies how the DQMH modules are launched. DQMH now uses Start Asynchronous Call instead of the Run VI VI Server method.
DQMH® up to 4.2.1
Linux RT (cRIO-903x) with Embedded UI enabled and using DQMH v3.1.0.18 - v4.2.1.46
Singleton modules cannot be used in a real-time application on Linux RT. The problem only shows when running the application from the run-time engine (run as startup app) with Embedded UI enabled.
The first symptom is the rendezvous functions timing out. Also, setting any controls of the main.vi inside the Module startup VI does not work.
There seems to be a bug with the Ctrl Value Set node on Linux RT when executed in the runtime engine with embedded UI enabled, where the value is not written to the control.
This NI Forums thread discusses the problem.
This leads to the module admin not being set correctly, and thus the External Launch property being false inside the module.
We created a workaround for this problem as part of our DQMH-related libraries:
⇒ DQMH RT Fix
Tested Devices and Cases
Used Software:
-
LabVIEW: 16.0f2
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cRIO 9030: NI Linux Real-Time x64 4.1.15-rt17-4.0.0f0 Firmware: 4.0.0f0
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sbRIO 9637: NI Linux Real-Time ARMv7-A 4.1.15-rt17-ni-4.0.0f1 Firmware: 3.0.0f0
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sbRIO 9636: N/A
| Target | Workaround | Start-up mode | Embedded UI | Result |
|---|---|---|---|---|
| NI-cRIO 9030 (LinuxRT) | No | Development | Off | Working |
| NI-cRIO 9030 (LinuxRT) | Yes | Development | Off | Working |
| NI-cRIO 9030 (LinuxRT) | No | Start-up | Off | Working |
| NI-cRIO 9030 (LinuxRT) | Yes | Start-up | Off | Working |
| NI-cRIO 9030 (LinuxRT) | No | Development | On | Working |
| NI-cRIO 9030 (LinuxRT) | Yes | Development | On | Working |
| NI-cRIO 9030 (LinuxRT) | No | Start-up | On | Not Working |
| NI-cRIO 9030 (LinuxRT) | Yes | Start-up | On | Working |
| NI-cRIO 9030 (LinuxRT) | Build with FP | Start-up | On | Not Working |
| NI-sbRIO 9637 (LinuxRT) | No | Development | Off | Working - FP-controls working but no FP-events |
| NI-sbRIO 9637 (LinuxRT) | Yes | Development | Off | Working - FP-controls working but no FP-events |
| NI-sbRIO 9637 (LinuxRT) | No | Start-up | Off | Working |
| NI-sbRIO 9637 (LinuxRT) | Yes | Start-up | Off | Working |
| NI-sbRIO 9636 (VsWorks) | No | Development | Off | Working - FP-controls working but no FP-events |
| NI-sbRIO 9636 (VxWorks) | Yes | Development | Off | Working - FP-controls working but no FP-events |
| NI-sbRIO 9636 (VxWorks) | No | Start-up | Off | Working |
| NI-sbRIO 9636 (VxWorks) | Yes | Start-up | Off | Working |
There is no difference if a display is connected to the controller or not.