A/D and D/A Boards for Linux?

Quadropleen+ asks: "I work in a lab where we do real time control of industrial hardware. To this point, we've been using several old A/D and D/A boards to control these processes under DOS, due to the anti-real time properties of Windows. Well, our cards are beginning to fail, and we're looking for replacements. I've been trying to get my advisor to move to Linux, and I see this as a great opportunity to leverage a better OS onto our machines. Does anyone have suggestions/experience with using A/D & D/A boards with Linux? What are the best and worst ones out there?"

Re:National Instruments

[Camel Pilot]

National Instruments only supports a Linux GPIB interface.

e-mail them and request more support.

Re:National Instruments

[rhk]

They have released a gpib driver and a daq driver, however, they also have more than sufficieint technical documentation for their cards on their web site that can be used to write drivers.

Re:National Instruments

[korgull]

I can recommend the National Instruments stuff.
I'm a Labview user for 6 years now and since 2 years I also use labview for Linux.
Another option is the comedi project (http://stm.lbl.gov/comedi/).
I'm sure that if you want to set up things in a fast and easy way, your best choice will be the National Instruments stuff.

Axiom Data Acquisition Boards

[jeremyphillips]

Back in the day, I used to work w/ Axiom D/A & A/D boards. They have PC104, PCI, & ISA cards. We had our best results with Axiom products. They would go through hell and back, were quite forgiving of bad wiring (after 48 hours straight, wire colors can start to merge together), were alot cheaper then other solutions of the time, and we had quite good luck getting support from them.

A quick glance through their site www.axiomtek.com [axiomtek.com], I came across a 16 channel board that supports "Red Hat Linux kernel version 2.2.X - AX509SP [axiomtek.com.tw].

Might want to give these guys a look...

There Are Many Options

[rhk]

In my work as a Test Engineer, I've used boards from Keithley-Metrabyte, Measurement Computing (Formerly ComputerBoards), and National Instruments. All work well with linux, providing you find the right drivers.

One good site for drivers is the Linux Lab Project. There are links to drivers for many different boards.

Another good project is the Comedi project, which maintains drivers for quite a few cards, and supports the use of RTLinux, RTAI, and card access from kernel modules.

My current favorite is the National Instruments E series boards. The drivers in the Comedi project are quite good, and the cards have an excellent set of features.

Elk is good...

[jimmydigital]

I'm using boards from Elk [elkproducts.com] in my home automation project... They are based in Charlotte and have some good kit. I'm using two digital IO boards and one analogue all on the same serial port.. with perl code to access the data. They have lots of other very cool stuff too though.

If you need realtime control...

[eric2hill]

Since you may want faster (realtime) response time for your application, you may consider using a PLC (www.automationdirect.com, www.siemens.com, www.modicon.com, www.ab.com) and just controlling set points with the computer. There are many many options available in this area, and a PLC is WAY reliable than a PC for critical control functions. Contact me through eMail if you'd like more information.

Real time control

[gepetto]

The suggestion that you look at PLC's is a good one, depending on what you mean by "Real Time". I have implemented many Intel/DOS-based solutions precisely because PLC's are very rarely anywhere near real-time. TI, for instance, has one of the fastest PLC's out, but the conversion times on their A-D cards is typically 250ms+. Doesn't do a whole lot of good to be able to read a port a jillion times/sec if the data there is old news. Makes for real smooth averaging, though!