simple data acquisition

[Anonymous]

I am very new to labview (although I did use it once in grad school for
a single project). I need to construct a system as follows

* step through 10 temperature settings on an oven (via rs232 comm to
the oven from a PC)

* record a constant flow of data coming into the PC from some sensors,
also over 1 RS232.

* Log the incoming raw data to a file

* if possible, parse up the string coming into the PC (CSV type fields)
and extract particular fields to be scaled and graphed with some type
of radio button type of interface (only one sensor value graphed vs.
time)

Can anyone point me at the blocks that I might use to build such a data
acquisition VI ?

My biggest concern is how to I set up a serial operation of 1. step
temperature 2. wait 10 minutes (or so) 3. take the sensor values and
log them to a file (probably adding an extra tag so as to identify the
current temperature programmed in the oven maybe something like ,10C,
in the CSV stream to be written to a file) 4. Repeat 1-3 over about 10
temperature steps.

Thanks! I am working my way through the beginner tutorials this week,
but any guidance will be greatly appreciated.

--Wulf

[Conseils]

The thing that seems to most frustrate people is the RS232 interface and configuring the connection and state of the RS232. Often people asking questions on RS232 don't fully understand what's going on and don't know how to approach the problem. Then of course some of it is physical and so you sort of have to be there to see the problem. Unless of course you document extrodinarily well!! (we live in hope, it keeps me in a job though if you don't ).

Find out early on (NOW) what type of controller you are going to use and what support exists for it already. (Some may have LabVIEW routines / examples already). What physical conections (cables) exist, are you going to have to figure out the cabling for yourself. Check out the serial port, it's getting long in the tooth now and not all PC's ship with one which means either a USB type RS232 or some form of card in the system. These USB RS232 keys can cause problems, they don't like long line lengths and some use reduced drive voltages. Search and ask about on the forum for specifics, models and experience especially if you can find someone with more 'local' knowledge for sources and expertise.

There is good support around for Eurotherm controllers on the forum especially if you go MODBUS and or OPC. They also give good support. Myself I prefer to use Eurotherm 800 and 2400 series, but then I have considerable experience with them. But you should go through the process of an active selection process, including requirements definition and analysis as this will affect the cost of the selected controller.

There are software device emulators that run on your P.C available and you could test out the whole thing without having to buy a unit - but the serial port will still be an issue!!!

The rest should be relatively straight forward as you can post samples and get specific, focused assistance on LabVIEW coding.
Probably best to ask focused specific questions, post examples... and you could have it finished by next Friday

Message Edité par Conseils le 05-20-2006 10:49 AM