Data Acquistion Hardware

[mbailey]

I am trying to set up a process in which we do incoming inspection on temperature device such as thermostats, thermistors and RTD's. I would like to be able to sample 30 devices in one setup. My proposed system would have a thermocouple located at each device and I would like to be able to record both the TC temp along with the state of the device. On top of this, I would like the data to be recorded in Excel. I'm not that familiar with data acquistioning and was wondering if anyone has any recommendations that may help me. I would like to have one set of hardware that would allow me to test all of these devices. Any help or advice is greatly appreciated. MB

 

[Skogsgurra]

There are so many options here. A single board computer with enough analog/digital channels and also logic channels for status input is probably the simplest way of doing what you need. They can usually be programmed in C or C++ or FORTH (my favourite language) and output data serially in space or comma (or any) separated Excel format and communicate with either a terminal program in the PC or with a custom written program.

There are also the National Instruments devices that are programmed in a graphic language, which is efficient but needs a good deal of training. NI is rather pricey.

Many PLCs of today can do what you want. And they can often (not always)communicate with a PC.

There are also solutions with an AD board and multiplexers that sit right in the PC bus and which comes with drivers that can talk to Excel.

I think that you need to get a consultant to sort out what you need and - if it is a good one - also implement the system. But ask two or more guys and ask them for a budget pricing before you let them have a go. These things can get expensive. Not that they need to be, but if you assume a lot of things and the consultant also assumes things, you end up in a mess of misunderstandings - and high costs as well as a probably less than optimal system.

Gunnar Englund

http://www.gke.org

 

[analogkid2digitalman]

mbailey:

Forsee some sort of T/C card or device with multiple channels that is compatible with the type of T/C's you plan on using. What programming languages do you know, this may dictate what hardware you choose and the interface method. You do not have to specifically use Excel (to record into). You can use tab or comma delimited text files if you desire, these are compatible with Excel. Forsee all of this running on a PC.

When you say state of the device, what does that mean? A themostat may have multiple states (off, heat, cool), while thermistors and RTD's really do not have a state, but rather a 'value'. Do you intend to input their signals into the above card too?

For the case of thermostat, will you be adjusting ambient environment to make sure the thermostat changes states?

Wheels within wheels / In a spiral array
A pattern so grand / And complex
Time after time / We lose sight of the way
Our causes can't see / Their effects.

 

[mbailey]

Thanks guys, when I say I want to read the state of the device, I mean for T-stats, either open or closed, depending on the type of device we are testing while suppling some voltage. For thermistors, I would like to be able to record ohms,understanding that I will probably need some type of circuit (or algorithm) to accomplish this while reading volts and current. Possibly the same thing for the RTD's. I used to program in Fortran many moons ago and most of those skills have long been burned away. That's why I'd like to have hardware that would dump directly into Excel via DDE and I can do whatever calculations I need to there. Don't know if such a device is available. I've looked at L##V##w for possibly some other applications in reading power meters to calculate efficency, but have not taken the plunge yet. Thanks, MB

 

[HEC]

MB,
Try "DataTaker" at

http://www.datataker.com

they have a wide range of dataloggers they also have very good analysis software that will export to excel.
Cheers


Mark Hutton

 

[IRstuff]

The simplest approach is to start with Labview and find hardware that's compatible with it. Labview should have the widest range of pre-canned routines for doing the data acquisition as well as performing calculations or exporting to other programs such as Excel. Labview requires little or no programming and its graphical interface and programming should minimize the grundge work.

TTFN

 

[m777182]

NI has a new USB-DAQ system.A USB-9211 has 24 channels and RTD input. Maybe you can use two of them simultaneously. I am using an 20 years old DAQ with 48 PT100 inputs, 12 channels V inputs and 48 DIOs.
m777182

 

[Madcow]

I like to use the Agilant 34970a with a 20 ch. mux.
Reads themocouples,volts and amps.
The Intulink software for excel adds a tool bar to excel
to allow direct downloads. Software is free.
Data logger is a little pricey.

http://www.home.agilent.com/cgi-bin...&CONTENT_KEY=205363&ID=205363&COUNTRY_CODE=US

 

[mbailey]

Thanks guys for your comments and suggestions. I'm leaning toward the Labview software and hardware. It's always good to hear other's opinions. MB