LabVIEW Real-Time Idea Exchange

Post an idea

At any one time, we have several complex LabVIEW-RT projects that run behavior experiments for us, taking multiple channels of analog and digital data while providing a complex series of audio and visual stimuli. For each project, there is an RT part that "runs" the Experiment and a tailored Host part that runs the UI, handles an Excel Workbook that specifies the various trials being performed, displays the data, and saves the sampled results to disk.

Each of these projects are developed using LabVIEW Project, and each LV Project has its own, unique name. When we build UI and RT executables, we would like an "automatic" way to associate them with each other. A "natural" way would be to use the "shared" information of their joint Project. There are ways to get the Project name in the Host UI code, both in Development mode and from an Executable.

I would like to propose that NI provide a Property or something similar for the RT side so that the RT code, at Run Time, could determine the Project from which it came. With both sets of code knowing their shared "ancestor", they could use this information to ensure they are talking to their proper counterpart. They could also use it to "mark" data structures (such as Files or Folders) that belong to them. For example, there could be multiple configuration files, one for each Project, but they could be uniquely identified as "<Project> Config.xml" (where "<Project>" is the name of the Project containing the VI, allowing the appropriate Configuration file to unambiguously be chosen at Run Time).

Bob Schor

View All (1)

We use cRIO's in industrial deployments all the time.

While a lot can be done to work around the lack of security offered by the built in FTP server, it would be much preferred if NI would add FTPS (and possibly SFTP) support, or at the very least, modify the existing FTP server solution to expose/support the following functionality:

* define users (currently, only the "password" field is used by the cRIO FTP server, the user name is ignored (or limited to the "admin" name only).

* define folder access rules on a "by user" level

Ideally, the current FTP server would be expanded further to include:

* secured file transfers via built in FTPS support, (or by adding FTPS VI's to the existing FTP toolkit)

* (secure binary transfers via built in SFTP server)

* open up and/or document how the current web configuration tool does the HTTPS file transfer interface

Currently, there are no easy way to allow our end customers to securely pull data log files remotely, and no way to prevent end customer from accidentally accessing or modifying sensitive parts of the application.

It would be possible to build a custom HTTPS file server on the cRIO, but I have several issues with this approach: it adds development and maintenance of another module to our code, it would most likely require another client side application for the customer to use, and most importantly: a lot of our customers have data collection servers set up to pull data over standard FTPS directly into their historians and their database systems.

View All (9)

It would be nice if attaching a thumbdrive to a cRIO / RT usb port triggered a "mounted" event or interrupt in the RT OS. Currently the only way to discover if a thumbdrive has been connected is to periodically run a file/folder info VI and see if one is present. It would be nicer if we could register a dynamic event and wait for it using an event structure, or similarily register for an interrupt event would work as well.

In my case, the use-scenario is a field maintenance person going out and manually plugging in a thumb-drive about once every 4 weeks to get the stored log files off of the controller. (No, we cannot use remote access in this case due to customer network restrictions.) So, in my case, I can easily use the polling solution, but if there is one thing I don't like to do, its to write polling code of any sort. It seems so wasteful. Other possible use cases could be to detect the presence of a thumb-drive and check for patch/updates, copy over new configuration files, etc.

Many networks have NTP (network time protocol) time servers locked to a GPS signal with claimed accuracy of better than 1 millisecond. NTP seems to be the de facto standard for distributing accurate time to systems accross a network. I would like to see a VI that can use this widely available protocol to set the system time with as much accuracy as possible. The RT Set Date and Time VI only permits specifying the time down to 1 second.

A forum contributor has provided a VI to read the NTP protocol, but uses the RT Set Date and Time VI to set the RT target system time losing any resolution beyond the second. This VI eliminates the greater precision available using the NTP protocol. The contributed VI also does not implement any of the advanced algorithms to improve the accuracy of using NTP over a network which are described at NTP.org and at links that may be found there.

Very tight synchronization (millisecond or better) of many RT targets is possible when the NTP protocols are fully implemented. I need accurate millisecond resolution on many RT targets over a wide (several thousand square miles) area. These RT targets recieve their data streams via radio telemetry so signal propagation time over the area is essentially zero. Processing of the data relies on the relative accuracy of time-tags generated at multiple sites.

View All (3)

If you try to select "Run As Startup" before having built the application you are stopped by LabVIEW with the phrase "The Real-Time application has not been built. You must build the application before deploying."

This is bad behaviour. Instead LabVIEW should silently do the requested task, including any prerequisite ones (the build), or at least offer me to grant it access to do so. The Run As Startup choice already includes the deployment option (no complaints from it if I have not done that yet), there is no reason why it could not do the build as well.

I'd like to create a timing source from an RT FIFO reference to drive a timed loop. The timing source would tic whenever there an element is placed into the RT FIFO, facilitating a timed loop to be configured for reading elements from the RT FIFO as they become available. This would only be available for blocking mode on read. Once the loop awakes, the user can then read the FIFO with a 0 timeout to get the data.

This would provide all the nice features of timed loops to loops that need to be timed by data showing up in the FIFO. Right now you have to place a while loop that blocks on the RT FIFO and wrap it in a timed sequence for CPU assignment and priority.

Also, combined with the idea posted for multiple timing source for a single timed loop, could be very powerful.

View All (6)

A number of times, I have found the Real-Time Clock configuration screen in Measurement & Automation Explorer to be very limited. With only the options to set the Time-Zone/Daylight Savings Time/UTC, I feel like there could and should be more!

Adding a feedback to show what the current RTC is set to similar to the Windows Clock configuration would be GREAT! Additionally, add the functionality of the RT Set Date/Time VI to Measurement & Automation Explorer.

We frequently run into issues where the Daylight Saving Time value is different between the US and the rest of the world (frequently=twice a year).

I believe all of this can be resolved by adding 1 layer of abstraction to translate a base RT system clock to the user-specified specifications to be added to timestamp data, schedule tasks, and so-forth.

View All (7)

Hello LabVIEW Users.

My name is Eisuke Ono, An Application Engineer at NI Japan.

One of our customer is requesting a function.

The function is to retrieve information of module fault from C Series I/O variable Node (Scan Interface).

I know that we can get the information of module fault through FPGA I/O node, but not through Scan Inteface mode.

The customer's application is embedded condition monitoring system. It runs 24/7.

So it is very convenient if he get information of module fault C Series I/O variable Node Error Output.

I agree his opinion.

What do you think?

Bestr regards.

Eisuke Ono

Having used our LabVIEW 2011 StateChart module with great success on a CompactDAQ system, I now have a new project using a CompactRIO 9075 which will
be controlling a hydraulic test unit. I would like to again use our StateChart Module so the functionality of the machine is understandable to all stakeholders.

The best NI example project I could find is the Chemical Mixing Example w/StateChart. It is exactly what I need except that it is a "headless" architecture. I need a 1:1 networked communication to my host PC for recipe entering and data logging much like the Bioreactor Example in the CompactRIO Developers Guide. See attached architecture jpg. I need to know how, specifically, to add a Host UI and incorporate network streams for the Host Command sender -> RT Command Parser.

In other words, what software architecture would combine the Chemical Mixing Example (w/StateChart) with the Bioreactor Example?

I think the configuration property pages for SoftMotion axes are missing the parameters for maximum velocity, maximum acceleration and deceleration for individual axes.

When performing single axes moves it is somehow easy to control these parameters because they are wired to the appropriate property nodes when configuring the move itself.

But when performing moves with axes in a coordinate space the move parameters given are for the resulting vector, resulting in unknown velocities for the individual axes.

When configuring the maximum velocity and acceleration/deceleration for an axis there should be the option to

a) Generate an error when the requested move can not be solved within the limits

b) Coerce the limiting value to its maximum and solve the move using the new values, generate a warning

View All (2)

View All (1)

Currently, when you add a new (not existing) cRIO controller and chassis to a LabVIEW project, there is no check as to whether this is a valid configuration or not. For example, you can successfully add a cRIO 9072 controller with a 9112 chassis to a project, even though the 9072 is a controller with an integrated chassis. I believe that the LabVIEW Project interface should notify the user (via dialog box) that this is not a valid configuration before they can add modules and start developing code to use an invalid configuration.

I did not see any options for this in labVIEW. I saw only you can play around writing and reading sound files and perform some manipulation to sound file.

Why not we compare two sound files extensively and indicate about similarities. For example, a system is running with constant sound(Motor is running in good case) and other hand the same system is running bad after some days or years(sound is different and louder with noise).

Second, if we can compare a sound with another sound, that would be interesting and possibly useful in applications. I know that many sensors out there for this operation but thought of interest to see it digitally in labVIEW.

If any thing wrong with my idea, please let me know.

I've been attempting to perform a relatively simple homing routine on a motion axis where there are two limit switches (forward and reverse) and a home switch located somewhere in the middle. The homing routine starts by advancing forward and if it does not see a home switch, it will continue in the forward direction until the forward limit switch is activated. At this point, the routine will reverse the direction of motion and continue searching for a home switch until it would eventually see it (thus it is guaranteed that the home switch is found.) Once the home switch is activated, the routine performs a fine tuning procedure by slowly backing away from the home switch (in the forward direction again) until it is no longer active.

When using a c-series servo interface module, there is a Stop Mode property that one can set for each limit switch to either stop immediately, decelerate or disable the drive (See fig. Axis Properties and Limit Stop Mode ). When the stop mode is set to Disable drive, the homing routine fails upon triggering a limit.

There are property nodes available to read the stop mode however the nodes are read only. (see fig. PropertyNode)

It would be nice to have the ability to programatically change the stop mode depending on the motion being performed. Our application requires that the drives be disabled upon activation of any limit switch under regular motion. However, during a homing routine since the disable drive stop mode impedes the routine, it would be benefitial to be able to change the stop mode to decelerate for the duration of the homing routine, and then change it back to disable drive once homing is complete.

I need a simple way to stop, from a PC, the startup application (if any) running on the RT system. This would work without prior knowledge of what is running on the RT.

This could be VI based solution that I could use in developing a startup upload application.

This would allow me to FTP new application files to the RT system as new startup code. Currently, if there is a startup application running on the RT system I cannot replace the application file since it is in use and I cannot stop the application without having access to the LV development system. I want too make this upload process into a user run software application for a PC connected to the RT system - without the user having access to the LV development software.

What do you need our team of experts to assist you with?

Request a quote Find the right product Place an order Get support on a product

How can we help?

Please enter your information below and we'll be intouch soon.

This field is required

Preferred communication method

Email Phone call

What do you need our team of experts to assist you with?

Request a quote Find the right product Place an order Get support on a product

LabVIEW Real-Time Idea Exchange

Provide a method for RT code to determine the name of its Project (such as a Property Node)

cRIO secured data transfers to host/clients and folder(file) access rules on a "by user" level for (S)FTP(S) server(s)

"USB mount" programatic event on RT

Allow setting RT target system time using NTP time server with high accuracy

Shared variable export to .csv should work with virtual folders

Make it possible to select "Run as Startup" without having to build the app first.

Create a timing source from RT FIFO reference

Real-Time Clock configuration in Measurement & Automation Explorer

Filesystem Rights in Web-based configuration and monitoring

Detecting C Series Module Fault through I/O Variable Node

Allow RT Scan Engine Fault Events to optionally include string data

Reboot RT into Safe Mode from MAX

Provide Software Architecture for using the StateChart Module on a cRIO with a Host UI.

Reconfiguration from console (mode)

Add maximum velocity and max. Acceleration/deceleration to SoftMotion axis property page

Installing NI-RIO for Use with Multiple Versions of LabVIEW

Remove Ability to Add Invalid cRIO Controller / Chassis Combinations in the LabVIEW Project

Sound comparison of two WAV files or in realtime application

Have the ability to set the stop mode for a limit switch from within LabView for NiSoftmotion

Ability to programatically stop any application running on RT system