Controlling multiple testing rigs remotely from one computer

[JATHL]

Hello,

I have 8 testing rigs that I'm trying to update to work independently from a central computer that controls them. I am planning to use a cDAQ with an integrated controller (probable NI-9132) since I do not need to have the faster cRIO to control my rigs and it would be easier to adapt the existing code to the new set-up.

However, I still want to be able to control the test rigs from the central computer to make it easier to control multiple rigs at once. I am thinking of using a TCP/IP or Network Sharing to do this but I have little experience in coding in LabView. Does anyone have an idea about controlling multiple test rigs over a network and help explain (in a general sense) how to use those functions to do it?

[GiantDeathRobot · Accepted solution]

Hi JATHL,

If you're new to LabVIEW, there's a good chance you have access to NI's Self-Paced Online Training. It would be worth at least skimming through Core 1 and Core 2. (If you have prior programming experience, you'll probably get through it quickly.)

Once you've done that, a couple other things to look at that would give you an idea of how to approach it:

• You'll probably end up with a variation of the Producer-Consumer architecture: http://www.ni.com/white-paper/3023/en/
• Specifically for two-way communication, take a look at the Queued Message Handler: http://www.ni.com/tutorial/53391/en/
• Once you have an idea how those work, Network Streams (crossrulz mentioned this in the other post) are how you'd implement those architectures across multiple targets: http://www.ni.com/white-paper/12267/en/

You could use TCP/IP as well, personally I'd go Network Streams. Built on TCP/IP, but a little easier to use in LabVIEW.

[Tim_McClung]

Can you elaborate a little bit more on what requirements you need in regards to control?  Do you just want to be able to view/modify the status?  Do these rigs need to be in some form of synchronization or awareness of each other?   What you need to control is going to have a big impact on the method in which you do it.  Any details you can provide on what you are trying to accomplish will help us give better advice.

Regards,

Tim

[JATHL]

Hello Tim,

The rigs are designed to measure the torque applied to multi-turn valves and they use a stepper motor to apply the torque. I need to control these stepper motors by telling them to turn to either a set torque or by number of rotations before changing direction. Additionally, I need to set the speed in which the stepper motor turns the valves and there is also a shut-off for when the valve breaks (i.e. pressure in system drops significantly) or when the measured torque exceeds the maximum allowed torque. There are also manual controls that I must implement that are mainly used to set-up a test.

Sychronization between rigs is not neccessary but being able to observe the data measurements with minimal delay is desirable. Additionally, more than one rig will be used at the same time but ussually not all of them. Therefore, I need to be able to specify which rigs need to be controlled. Also, since most inputs (rotation speed, max torque, etc) are the same for multiple rigs in a test, it would be desireable to change these inputs for multiple rigs at once yet maintain individual control for troubleshooting.

[crossrulz]

Look to the STM library.  It is a free library available through VIPM.  Use it to establish your communications between a single cDAQ and the main computer.  If you do this right, you can dynamically call that VI that does the communication with that cDAQ to have as many of these connections as necessary.  For communicating with these connection VIs, I would use an User Event.  User Events are a lot like queues, but they are broadcasted to everybody who is registered for the event will see it and be able to react to it.

This will quickly turn into a complex architecture, so hopefully you can get somebody experienced to help you through all of this.

[JATHL]

Hello Crossrulz,

While there are a few people that can help me with learning to code in LabView, none of them have experience using the STM library, VIPM, or User Events. Do you know of any resources that I can use to help me familiarize myself with these topics? 

Additionally, since VIPM is an add-on for LabView that I don't currently have and I'm using a company computer which prohibits me from installing software without permission, I don't know if I will be able to get access to VIPM. Therefore, do you have any other suggestions to solving this problem in the event that I am unable to use VIPM?

[Tim_McClung]

Which version of LabVIEW are you using?  If I remember correctly 2015(ish) and beyond installs VIPM automatically for you.  

VIPM isn't difficult to use so I don't expect you'll have too much trouble there.

For the actual code packages after you finish with VIPM check the example library in labview under 'Help'.  There's often examples that will show you how to work with a code set.  

Best Wishes,

Tim

[JATHL]

Hello Tim,

Thank you for letting me know about the automatic VIPM installation but I don't think that I have it. I do have LabView 2015 but, when I click the "Find LabView add-ons" link under "Find drivers and add-ons", I am sent to NI's LabView Tools Network webpage.

If I am unable to use the STM library, do you think that using Network Streams would allow me to accomplish my goal for this project?

[crossrulz]

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wrote:

If I am unable to use the STM library, do you think that using Network Streams would allow me to accomplish my goal for this project?

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The STM library is just a nice package on top of the built-in TCP/IP functions.  It adds information like the message length and metadata for you, making it quite convenient.  You can still do this yourself with TCP or Network Streams.

[JATHL]

Hello Crossrulz,

Thank you for the conformation.

Additionally, I realized that the VI that I will be using in the cDAQ has an ideal front panel for my application. Is there a way to mirror the front panel of the VI on the cDAQ to the VI on the computer?