LabView Real-Time, WEG VFDs, sbRIO

[Russ_in_Louisville]

WEG provides their VFDs with pre-loaded software and all the device cares about is a dry contact (4-20mA). The device can also provide a voltage feedback.

So for LabView, Real-time target, sbRIO is there anything special I need to do other than provide a while loop with a AOXX programmed with a range (4-20mA) for 0-60Hz?  Program with VISA or anything like that?

An example would be helpful.

Pls. keep in mind I am a novice.

[BenDAE]

Let me see if I can make sense of this.

WEG (a company) makes a variable-frequency drive (VFD). One of these VFD's provides a voltage or current. How is your sbRIO connected to your VFD? What is AOXX?

[Russ_in_Louisville]

BD: WEG (a company) makes a variable-frequency drive (VFD) Me: Yes

BD: One of these VFD's provides a voltage or current: Me: Yes for feedback and is driven by one 4-20 mA input from the controller (sbRIO in this case)

BD: What is AOXX. Me: It's the analog output in the LV VI block diagram. Connecting the physical sbRIO device to the VFD is not the issue an is straight forward. My concern is the programming of the VI with RT target. The vendor (WEG) reports the VFD is preloaded with software and only cares if it is physicaly connected to a contact. The LV VI programming is where my question is. Some of the other feeds regarding VFDs make reference to VISA. I'm just wondering if I need to use that, any PID, etc. Basically, how is the controller (sbRIO) programmed (LV VI) to control a controller (VFD)?

[BenDAE]

Depending on the sbRIO device you have, the options for signaling can be different (DO or AO or both). Would you mind explaining what part you're having issues with in terms of programming? Letting me know what device you have would help as well.

[Russ_in_Louisville]

It's the sbRIO 9641. There is a correction too. The 9641 has only voltage analog output. That's fine because the VFD has voltage input.

BD: Would you mind explaining what part you're having issues with in terms of programming?

Me: I don't know even where to begin with this one. Do I connect my AOXX to a scaling/mapping? How is the VFD represented? Is it just an indicator in the block diagram?

[BenDAE]

Russ,

Why don't you try looking at this getting stated guide? http://www.ni.com/singleboard/setup/

I am here as well as the rest of NI community when specific programming questions come up. We do also offer training, if that would be of interest to you.

[Russ_in_Louisville]

Ben (or anyone else out there),

That is a lot to wade through when I suspect it's simple for an engineer at Core 2 or above. I've been through the online Core 1.

Also, I do not physically have the sbRIO device.

Here's what I do have (see attached too).

The scaling and mapping function is assigned to linear (i.e. y=mx+b). In this case, the VFD range is -60 to 60 Hz (running backwards and forwards). m=6 since -10V≤x≤10V

I have a project set up with the RT target and a VI for the VFD control (see attached). Do I represent the VFD with the gauge shown? Since my VFD can give an analog input to the sbRIO for monitoring, how can the gauge do that? Once I replace the knob with the AOXX, how does the program know it's -10 to 10V analog?

If I want to connect it to other sub VIs (i.e. system response to low fluid flow, etc.), do I need to connect shift registers to the edge of the while loop?

There's not really a good example of this entire problem (to my surprise as much as VFDs are used) in the online NI world or the LabView examples. Should be a standard template with LabView, out of the box.

[BenDAE]

Russ,

Thank you for attaching your screenshot. cDAQ's can be simulated using MAX, but this is not the case for sbRIO's. In order to program an sbRIO, you'll physically need one. For your reference, Core 2 doesn't even touch Real-Time programming. That is it's own course, so this is actually not as simple as you would think. I would advise you to move this discussion forum to the RT forum for access to users with more RIO experience. http://forums.ni.com/t5/Real-Time-Measurement-and/bd-p/280 Be sure to reference this forum when you post. I would also look at the example RIO code for a sense of how to input and output signals to and from the hardware. Be sure to download the NI-RIO driver to get those pieces of example code.