Interfacing

[Hafidz]

I'm doing a project titled "Weather Monitoring system using LabView".
This is the first time I'm using LabView.
I really need help to do this project.

My problems are
1. How can I connect my weather sensors to PC. I know the sensor will
give
an analog signal (voltage), do I need a Analog Digital Converter to
interface it with the program that I build using LabView or I just
use
LabView to convert it for me.
2. I will use at least 3 sensors and i will connect them through my
COM Port.
How can I separate the signal to make sure it can be read for my
LabView
Program.
3. Is there any interface circuit that available through the web.
Thanks.

[Tom]

Have you experimented using a DAQ device?


"Hafidz" wrote in message
news:afbaf8ed.0207031936.aee447@posting.google.com...
> I'm doing a project titled "Weather Monitoring system using LabView".
> This is the first time I'm using LabView.
> I really need help to do this project.
>
> My problems are
> 1. How can I connect my weather sensors to PC. I know the sensor will
> give
> an analog signal (voltage), do I need a Analog Digital Converter to
> interface it with the program that I build using LabView or I just
> use
> LabView to convert it for me.
> 2. I will use at least 3 sensors and i will connect them through my
> COM Port.
> How can I separate the signal to make sure it can be read for my
> LabView
> Program.
> 3. Is there an
y interface circuit that available through the web.
> Thanks.

[Filipe A.]

Hello;

NI has data acquisition boards that allow eternal signals to be read and processed by the computer. You don't even need to use the COM ports for that since the DAQ boards use a much better data transfer method which is the DMA channels of your computer.

The information you need to put togheter so you can better choose the DAQ board that better meets your application needs are:

1) Number of channels
2) How fast your sample rate needs to be
3) What is the input voltage range of the sensor signals
4) Do you need any kind of signal conditioning

Without having the answer for the questions above, I recommend you to look at the E-series DAQ boards (www.ni.com/catalog), that covers most of the applications.

Hope this helps.
Filipe A.
Applications
Engineer
National Instruments

[mikeporter]

If I am reading your question properly, you are trying to read 4 channels of analog data through a serial port on your PC. Correct?

Doing low-speed analog acquisition through a serial device is a very easy thing to do. There are a number of companies that make small external boxes that read as many as four analog channels. Two companies that come to mind right off the top of my head are Opto22 in California and DGH in New Hampshire (both here in the US).

In terms of interface circuitry, assuming that the devices have voltage outputs, the interface circuitry should be as easy as hooking up the wires.

What sensors specifically are you using, and what do their outputs look like?

Mike...

[Hafidz]

I'm not sure yet about the sensors, but the output will be in VDC.

Thanks for your help

[Hafidz]

sorry, i miss understood your question.

I will convert the analog signal from the sensors (VDC)into digital
signal separately.
I will try to output it using Labview.

[PdB]

Mikeporter gave you the best advice because they are cheap, wheather-monitoring takes place outside and RS-232/485 is easily wired over several meters.
If you prefer an all NI solution, I would take a look at the Fieldpoint industrial remote I/O modules.

Good luck on the project, Patrick de Boevere