Labview is a general purpose graphical programming language targeted specifically for data acquisition and testing. It is object oriented, scalable, and easy to use. It works well in top down design, bottom up design, or a combination of both. From it's earliest conception, it was intended as a platform for the interaction between a computer and other devices. The code is compiled, not interpreted. I use Labview with Windows 95/NT 4.0 on a daily basis. Most of the programs are used in development or production testing of 500 - 3500 hp centrifugal air compressors. Most tests have between 50 and 100 inputs. I have been using it for about two years and am extremely satisfied. For data acquisition and control, I have also used Qbasic, HP Instrument Basic, Visual Basic, and C. In my opinion, there is no comparison. I have replaced all of the text based programs with Labview ones. The new programs do two to ten times as much, but only took a fraction of the time to write. Labview is an implementation of the "G" programming language. (This has nothing to do with machine tool control G codes or Gerber codes.) It is not flowchart based programming. Rather, it is a graphical analog to As a programming language, there really is no limit on the number of IO devices it can handle. These, however, will be limited by your hardware. I am not sure what you are planning to use as an interface to the PLC's. Serial comms are very easy. I use GPIB and ethernet primarily. All of my pressure transmitters are ethernet devices. Low level TCP/IP data communication is very easy. For the above compressor testing software, I can take data and do an entire test from my office (it's in another building). The Internet Toolkit includes a HTTP CGI server written entirely with Labview. You can access the ongoing test data from anywhere in the company's intranet or, even over the internet just by firing up Netscape. Are you using something like device net or Field bus? Labview can handle these too, but you will need to buy an interface card. Enough of the soapbox, I can go on for hours about the virtues of Labview. It only takes a few minutes to list the weaknesses. The biggest is cost. My Labview professional edition cost about $3500. I am not sure what the latest price is. I do not know what the price of the base package is either. It used to be about $1000, but it may have increased. I think they also have a package called the Test and Measurement Suite. It includes NI's C development system (Labwindows CVI), their Visual Basic/ActiveX control library, Labview and all of their add-on toolkits. As far as advice goes, I would begin with your strengths. Do you have any experience with any of the popular programming languages, particularly C++ or VB? If you are, pick something like a set of ActiveX controls or a C based data acquisition environment like Labwindows CVI. VB or Visual C++ are relatively cheap compared to any of the specialized SCADA, HMI, or DAQ software. Next, look at the project requirements. Are you just doing logging, trending, and alarming, or is there more to it? Are you looking for a canned package that does the above right out of the box? If you are, you might want to look into one of the factory automation packages like Wonderware. Another possibility is another National Instruments product called Bridgeview. I have not used it, but essentially it is Labview with a bunch of built in functions and examples specifically for large scale industrial monitoring and control. It includes a real-time database and functions for handling instrument tags, etc. The problem is that it costs even more than normal Labview. This is what I would use if I was in your shoes. Labveiw or Bridgeview really shine if in addition to logging, alarming, and trending you also need to do some analysis. The full version of Labview includes a plethera of signal processing (FFT, Convolution, Complex FFT, Hilbert transforms, etc), matrix manipulation, statistical, curve fitting, root finding, optimization, and numerical functions. Resources: There is a mailing list similar to the PICLIST that specializes in Labview. I do not have the exact address, but I will get it at work tomorrow. The list server is somewhere at www.pica.army.mil. The people there are very helpful. The traffic is about 40 messages per day. National Instruments' website, www.natinst.com has a bunch of sales information along with a large database of example programs. TECHNICAL SUPPORT IS FREE. Although, you get a shorter queue and a smarter support person if you pay for it. There are at least a dozen books out there on labview. They range from a beginners guide like "Labview for Everyone" to "the bible," "Labview Graphical Programming," by Gary Johnson. A new one out that I have yet to get, although I have heard it is very good is "Labview Power Programming" by Gary Hedstrom (you might want to verify the spelling on his last name, I am just going from memory). The bottom line is: Will Labview work for your application? Absolutely, it has been used for things as diverse as talking to PICs (through the serial port), controlling particle accelerator experiments at Lawrence Livermore National Labs, and monitoring the motion of Sojurner (the mars rover). The important things to look at are your experience, your budget, the exact application, and the project timeline. If you have any more questions, you can send them directly to me and I will give you any help I can. Paul A. Brown P.S. If you are wondering how long it will take to learn Labview, obviously, there is no pat answer. It will depend on your background and ability. Typically, I have heard it takes 1-1/2 to 2 weeks before you really produce a useful program. I would start with the on-line tutorial under the help menu. Then, go with the "Learn Labview By Examples" lessons. Pick a simple program to start out with. Use the examples that come with Labview, they can be very helpful. Go to NI's web page to look at some more examples. I can give you some other web sites where you may find some helpful examples as well. ___________________________________________________________________ Get the Internet just the way you want it. Free software, free e-mail, and free Internet access for a month! Try Juno Web: http://dl.www.juno.com/dynoget/tagj.