LabVIEW 2013 Real-Time Module Help
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Keep the following considerations in mind when using an NI Linux Real-Time target:
- The FTP server is disabled by default, and you cannot use it in safe mode. National Instruments recommends using WebDAV as the file transfer mechanism for improved security.
- Virtual memory is supported, which implies the following:
- A process crash restarts the process without restarting the target.
- Monitoring the largest contiguous memory block does not provide useful or necessary information on NI Linux Real-Time targets.
- System Exec VI is supported.
- Time zone changes do not require a target restart.
File System and Directory Structure
- The file system is case-sensitive.
- Directory paths display in Linux format. For example, paths use forward slashes and do not contain drive letters. If you open a VI created for ETS or VxWorks targets in an NI Linux Real-Time target context, the Windows-style paths automatically convert to Linux-style paths.
- NI Linux Real-Time targets enforce file and folder access permissions. Refer to the KnowledgeBase for information about these permissions.
- The RTOS deletes the content in the temporary folder /tmp on target restart. The temporary folder allocates space from RAM up to a maximum size of 64 MB.
- The c:\ni-rt directory and ni-rt.ini configuration file do not exist on NI Linux Real-Time targets. Refer to the KnowledgeBase for information about the directory mapping on NI Linux Real-Time targets.
- WebDAV is enabled by default.
- SSL is enabled by default.
- NI Web-based Configuration & Monitoring is available in safe mode.
- It is only possible to configure a target reachable via IP address (DHCP, link-local, or static). mDNS is used for target discovery.
- You can log in to a target using NI Web-based Configuration & Monitoring, SSH, or a serial connection. Refer to your hardware documentation to learn about enabling SSH on your RT target.
||Note National Instruments recommends you set a password to log in using SSH or a serial connection.
- To reset a forgotten administrator password, you must physically access the target and reset all settings to the factory default. Contact National Instruments for assistance with this process.
- Your target creates an admin user that is equivalent to the root user in Linux systems.
||Caution Do not create users in NI Web-based Configuration & Monitoring with the same name as system accounts. For example, do not create a user named root or ssh. Doing so overwrites the system account.
- SSH supports public keys as an alternate form of authentication.
The LabVIEW Real-Time Module does not support certain LabVIEW features for VIs that run on RT targets. For instance, if you attempt to deploy and run a VI that has unsupported functionality on an RT target, the VI might still execute. However, the unsupported functions do not work and return standard LabVIEW error codes. The LabVIEW Real-Time Module does not support the following features on RT targets that run the NI Linux Real-Time RTOS:
- ActiveX VIs
- NI TestStand VIs (ActiveX-based)
- .NET VIs
- Report Generation Toolkit VIs
- Windows Registry Access VIs
- Report Express VI (Uses the unsupported Report Generation Toolkit VIs)
- Graphics & Sound VIs
- Database Connectivity Toolkit VIs
- Menu functions
- Cursor VIs
- IrDA functions
- LabVIEW Digital Filter Design Toolkit VIs
- File System Web Service LabVIEW API
- Analysis Workspace to Reduce Jitter in Mathematics and Signal Processing VIs
- Call Library Function Nodes that access an operating system API other than NI Linux Real-Time
- Open/Create/Replace File function interactively using a file dialog box
- Clear indicators when called option of the Execution Properties page
- Auto Configure option of the Create Histogram Express VI
Certain Advanced TDMS functions
Certain MathScript functions
Certain MathScript functions are supported on RT targets only when you assign the output of the function to a MathScript variable.
- Output Page of the LabVIEW MathScript Probe window—You can use the rt_debugoutput function to send debug strings to the standard output device instead.
- Largest Available Memory Block Property Node—This property node does not provide useful information for NI Linux Real-Time targets and returns an error if used. Use the Free Physical Memory property node instead.
Event structures on RT targets do not support events associated with user interface objects, such as VI front panels or controls. For example, associating the Value Change event with a control does not work. RT targets support only user events.
- Latch Until Released and Switch Until Released Boolean mechanical actions—Refer to the KnowledgeBase for information about why these Boolean mechanical actions do not work on RT targets.