Data Acquisition Card or PLC

I would like to have your opinion on whether to use a data acquisition system or a PLC system for an Air Leak Test. It's a simple one to measure pressure decay using pressure transducers. Keep in mind that I do not have any of the components (Hardware or software).
The data acquisition card to be inserted in the PC and the system to be monitored using Labview. For the PLC system I will get the controller, software...
I guess I would like to know what will be more efficient (Considering cost and application). Is it necessary to get the PLC system or the DAQ would do it just fine.

Greetings R-Phil,

Generally - in my openion - the PC-based measurment and control is the easiest way in lab tests.

I think it is not necessary to get the PLC system for this task.

You 'll plug the DAQ card and play with it using LabView in few hours maximum, BUT it really depends on other factors:

1- Time of learning (Do you know LabVIEW or PLC programming or both?)
2- Cost (for example LabView is expensive .. visit www.ni.com, also HMI packages aren't cheep too, another option is to build your softwae using VB or somthing )
3- Do you have a critical operation or process in your test that needs high reliable system (The PLC wins here)

I think you should state more details about you and your application to get more detailed openions.

I am sure that the guys here will give more information than I did, But I hope I gave any help.

Have a look at this

http://www.dataq.com/gl/?source=googleda

Thanks
Well I don't know labview but I am a pretty quick learner and going through the demo I think I can get it fairly. I never used a DAQ before but it seems that all I'll have to do is get the right card, configure the driver and program labview (maybe more complicated than that, I don't know). On the other hand I know PLC programming.
For my application, I will have approximately 13 pressure transducers (analog), 2 temperature sensors, and a couple of solenoid valves. It will consist of pressurising the components with air, and identifying the leaks by drop of rise of pressure.
I tried to come up with a quote for a controller (ML 1200 package) and it was about $2,900 not including HMI.
However at first I was checking out the DAQ sytem and I was thinking about using the base Labview $995 (or not good enough?) and a DAQ card (I think they run about $600).
I think that's it. I am a beginner so I need inputs please
Thanks again for your help.
By the way its for an industrial testing.

Phill,

How much information and what frequency are you looking to obtain?

Do you know the I/O you will require for your application?

Is Time date stamping required?

Would you be able to use an Excel spread sheet for your information?

Stephen
I am no sure yet how much information. I say about (5K words probably less)
10 Khz
For the I/O I have 13 pressure transducers 12v and solenoid valves (not selected yet)
Time date stamping is not required.

R-Phil,

If you really need to sample at 10 KHz (every 100 microseconds), you're out of the range of what you can do with a PLC.

Phil,

Would this be an option? - http://www.entertron.com/logger.htm

Actually when I said 10khz, that was the minimum sampling rate needed for for the DAQ card. The application is to measure the pressure decay, observe the the pressure status.

First suggestion:
Well, I may suggest a reliable solution with resonable cost:
These people www.tri-plc.com are offering a very non-expensive PLCs with many capabilities (e.g analog I/O, PID, 2 ports for comm, modbus protocol ..)

We used this unit in one of our small projects, It was an automatic voltage variac that the desired voltage can be set through a software installed on a computer. So we used the Tri-logi PLC as an interface between the PC and the stepper motor that rotates a shaft varing the output voltage ... any way .. It was a headache, but the small PLC baby was going just fine and the cost was nothing comparing to AB micros !!

Another advantage is that this PLC can be interfaced serially with a simple command-response ASCII charcters.

So you can use any programming language to send/recive to/from the PLC(e.g. LabVIEW or visual basic)

Seconed suggestion:
www.autoamtiondirect.com offers many low-cost, powerful PLCs. See if they can help you.

Third suggestion:
If you decide to take the PC-based solution (Plug-in card) you can get low cost DAQ cards from this company www.adlinktech.com

They are also offering FREE labview VIs that will make the connection between your card and Labview a piece of cake!

Hope this helped you.

R-Phil said:

Actually when I said 10khz, that was the minimum sampling rate needed for for the DAQ card. The application is to measure the pressure decay, observe the the pressure status.

Click to expand...

The answer:

If you really need to sample at 10 KHz (every 100 microseconds), you're out of the range of what you can do with a PLC. (( said by Steve Bailey ))

Click to expand...

So my third suggestion is the only valid suggestion for your application.

Also Stephen Luft's suggestion is good for your application.
http://www.entertron.com/logger.htm

ayman

So my third suggestion is the only valid suggestion for your application.

Click to expand...

Could you explain to me why?

R-Phil,

The third suggestion is the only one that works because of your required sampling rate.

Why do you need to sample at 10kHz?
Isn't your air test somewhat long?

Also, what are you doing with all the data that you are sampling?
Are you storing it in a database?
If so, it would most likely be easier to use the PC and DAQ.
You can also try
Measurement Computing for a DAQ.
And try Softwire for the software.

We haven't set up all the specifications yet. I was handed this project with little information, and my supervisor at first said he would like a DAQ card with at least 10 KHz (Above is fine). That's what I meant, I really don't know too much about sampling rates. And yes the Air Test will be long.
When it comes to storing data I don't know exactly what they want. They just told me that they want to see the pressure so that they can tell when it goes down or up.

... and my supervisor at first said he would like a DAQ card with at least 10 KHz (Above is fine)...

Click to expand...

Yes. If you are choosing a DAQ card, these high sampling rates are seem to be "normal", but in case of the PLC it isn't the same, PLCs are not made for these kinds of works. Yes, I heared the term "high speed analog input modules" but I don't know how speed it is?

So, You may start from here: Do I really need this high sampling rate? If so, PC plug-in DAQ card is my choice.

Then tell us what where are you.

Also, a good tutorial can be found Here