how to program with simulated devices

[newbieeng]

hi all

I am very very new with LabVIEW actually it will be my first project with labview and NI devices. I am preapering a test setup with NI instruments that are

NI 9188 [DAQ chassis\ 8 channel]

NI 9214 [16-Channel Isothermal Thermocouple Input Module]

 

NI 9203 [8-Ch ±20 mA, 200 kS/s, 16-Bit Analog Current Input Module]

NI9263 [4-Channel, 100 kS/s, 16-bit, ±10 V, Analog Output Module].

I do not have these devices for now and I want to prepare the LabVIEW program before we get it. I read something about "simulated devices" in LabVIEW but I am really new with it as I mentioned before. I want to mention about the project a little. we desire to measure temperature and pressure from an evaporator and collect data after it we use it on preparing pressure-enthalpy graphs.

Could someone help me on this. I really do not know LabVIEW exactly. I am studying it. I have LabVIEW Academic Suit Premium 2009.

[AdnanZ]

Have a look at the following page:

Getting Started with NI-DAQmx

There is an explanation of how to simulate DAQ devices and how to program them in LabVIEW.

Also, I would recommend going through some LabVIEW Tutorials.

[newbieeng]

thank you for your answer.  Now, I am reading it. I wish to find my answers there. but generally these reinforcements are too generall and not helpful for special targets. Thank you again.

[newbieeng]

I really could not find what I am seeking. I have studided all tutorials that comes with LabVIEW and I really could not find what I am seeking. 😞 maybe that's because I am new in data acquisition. 😞 How can I simulate my system? I have to simulate temperature and pressure data for the daq and after I have to use them for programming. I have 128 thermocuples and 4 pressure transducers to take the signal. how can I simulate and programme it?

[smercurio_fc]

The simulation of the DAQ hardware is just for that: it allows your code to run by proving a software replacement for the DAQ hardware. It will allow you to go through the motions of configuring the cards and "collecting" data, but it cannot replace the actual signals the DAQ would receive. It will generate some simulated signals so that you can check out if the logic in your code is basically operational. At some point, though, you need to have the actual hardware. Thus, if your signals may have noise or coupling interference, you will not know this until you connect the actual hardware. That said, the simulation of the hardware will take you far enough along that you can write the basic program.

[DFGray]

What you need is a specific hardware abstraction layer for your application.  The easiest (and current "best practice") way to do this is using LabVIEW objects.  Unfortunately, this is a relatively advanced topic, and could cause you to spend far more time than necessary to get things working.  If you are interested, you can get a paper on the topic here.  I would definitely recommend learning LabVIEW objects sooner rather than later, but get the basics first.

[Kyle_K]

The concept of simulating a device is to create a virtual device in max that you can use in your program as if it was real. Realize that for data acquisition, we go from physical phenomenon (temperature, pressure, etc.) to a sensor, to a data acquisition device (DAQ) into MAX, into LabVIEW. With a simulated device, the software beyond MAX doesn't know the difference but since it is simulated, it cannot show you real data. 

You can find how to simulate a device HERE . 

Once you have made your simulated device in MAX, write your program in LabVIEW as if you had real hardware.

Kyle K.

[newbieeng]

Thank you very much guys. while I was studying tutorials of Labview I simulated a NI-PCI 6225 Dev 1 but in my MAX I cannot see the DAQmx TEDS Interface under the "Devices and Interfaces" section like the link sent by Kyle. How can I get it? Do I have to install NI-devices drivers or sth else? by the way the accuracy of measurement via simulated devices is not important for me. My main aim is to understand how to take measurement with these devices. And also I want to prepare all the system simulation in Labview. For instance, I need to measure temperature and pressure from test setup for this purpose do I need to prepare a signal generetion and a DAQ devices?

[Kyle_K]

newbie,

In the NI search bar on our website for "TEDS" will provide you with many resouces about TEDS. One of those pages found Here explains that not all hardware support TEDS, and that you can find out if your device does or not by searching its specifications document (available online with a search of any of our products). In terms of software, DAQmx 9.0 and newer will contain all you need to communicate with a TEDS device.

Kyle K.

[djs_at_eaton]

Correct me if I'm wrong.  What I think you want to do is simulate data coming into your program as if there were real devices and real transducers connected to your computer.  I don't think that's possible yet with LabVIEW or NI-MAX.

However, it can be done.  I've done it several times.

You need a model of your system.  You need to write your code so it can call either the model or the real devices.  The simulating code needs to produce waveform data that looks like real data to the program.

You can find more information and sample code at https://decibel.ni.com/content/groups/west-michigan-labview-user-group?view=documents.  You can use these links too.  https://decibel.ni.com/content/docs/DOC-12216  https://decibel.ni.com/content/docs/DOC-12215.  The links are to sample code and a presentation I gave to the West Michigan user group about a year ago.