How to start a software data collection and processing?

[tribo1617]

Hello NI-Community,

I'm new to the whole area of NI, excuse me when I'm wrong here. Also I'm a german student and my english is not perfect yet. So please consider this, too.

So I'm starting a project about modifying a test bench which is mostly analog at this time. I want to develop a software (with LabVIEW) to collect data output and with it the software should regulate what is set to be, e.g. temperature. So I'll need to modify the analog thermocouple to an electrial, some DAQ-hardware and a program which I have to develop with LabVIEW to complete my system. The data that should be handled by the software are: temperatures, pressures, vibrations. Everything should be controlled with the software.

What general things do I have to know? Which DAQ could I use? Any tips on how I get a good start?

As I said this area of engineering is complety new to me, and I hope someone can help me or at least give me the right direction where I should continue my investigations. My problem so far is that the possibilities of LabVIEW etc. are so huge, that I'm kinda lost in there.

Sincerely yours

[crossrulz]

How many of each signals do you need to measure?  How are you doing the control?  What type of signal does your stimulus need?  How fast of a control algorithm do you need?  How much budget do you have?

My suggestion is to find your local NI rep and have a nice long sit down to discuss your requirements.  They are usually really good about making solid suggestions.

[tribo1617]

How many of each signals do you need to measure?

- I'm not sure yet exactly, but about 4 temperatures, 2 pressure and maybe 1 vibration signal

How are you doing the control?

- By control you mean what is regulates the whole system? The goal is that the software (the LabVIEW programm which I have to program) controls the input/output signals etc.

What type of signal does your stimulus need?

- I don't know, where to find out what stimulus I need/have?

How fast of a control algorithm do you need?

- I don't know, in which case is this important?

How much budget do you have?

- I don't know yet, since I'm at the very beginning of the project and my professor didn't tell me. But I would guess something around 1000-5000€.

I'm not sure if we have something like a local NI rep, can check that. I'm mostly on my own with this project. Hope this informations help you to help me further.

Thank you so far!

[crossrulz]

So you basically know nothing.

You need to do is figure out what sensors you want to use.  These will dictate what DAQ hardware you will need.  And you also need to know the control design: inputs to the control algorthim, outputs, update rate, how much jitter you can allow.  This will dictate what platform your code will need to run on.  In 99% of cases, a Windows PC running software is NOT good for control.  Depending on the signals you need, you may be able to use an R-Series FPGA board to run your control logic and then just pass whatever data you want logged to the PC via a DMA FIFO.  The other option I throw out there is cRIO (which is what I almost always use for control systems since it is more rugged).

So the very first thing you really need to do is collect and organize your requirements.  This is the first thing you should always do in engineering.  Without requirements, you have no clue what you are actually doing.  And you need your requirements to be specific (ex: control temperature with a rise time of X, overshoot of Y, and steady state error of Z).