viSci

Unfortunately the native sound card library does not include a way to poll for the buffer pointer. You can get the 'is playing' status but that would probably not avoid glitching. I think the correct way to do this is with a ring buffer scheme. You might have better luck with this library since it can assign multiple output buffers... http://www.zeitnitz.de/Christian/waveio?mid=9

You might look into this library... http://www.zeitnitz.de/Christian/waveio?mid=9

All - thank you for the great replies! I think I was just saved from a serious potential error in judgement. I am now settled on changing my original attempt at a fixed price contract to a much simpler consulting by the hour approach. I have tried to offer a best estimate of the hours required but a large body of inherited software that is unfinished and untested has too many uncertainties for me to be held accountable.

You are the third person in a row to tell me that. But sometimes one must try to balance risk with the need to keep work coming in.

I am in the process of formalizing a contract with a company that has been known to have had prior issues with LabVIEW developers and has adopted a tough talking somewhat litigious tone. I am considering what wording I should put into a Software Development Contract that will protect me from any liability in the event a bug in the software should damage the clients property. Has anyone had experience with this? Or perhaps could suggest a contract template to start off with.

If you ever think of taking a dip into .net drawing here is some example code (LV2013) to get you started... Forgot to mention that the example drawing vi is in the Test Folder AntiAliased Drawing.zip

Been down this road and after fighting with the 3D graph and 2D picture control I became dismayed at LV's lack of modern 2D graphics with basic features such as anti-aliasing and the ability to define a hierarchy of graphic objects. I was hoping someone would have tried to bring some SVG action in LV but instead had to settle for .net which is actually pretty nice. I spent about 2 solid weeks wrapping .net graphics and produced some very nice anti-aliased radar type graphics. If interested I will try to wrap up my .net libraries and post in the CR. In the meantime you can see some of the results in my portfolio at www.viScience.com (Avionics 1553 Simulator)

Just poking this thread to see if anyone is still working on AMQP or 0MQ...

Here is a discussion on the subject... http://forums.ni.com/t5/LabVIEW/Is-it-possible-to-write-waveform-data-to-Citadel-in-LabVIEW/td-p/1637172

Just curious, can you use the remote app ref to get 'All VIs in Memory'

The standard route to getting your Instructor Cert. is to go to the weekend training in Austin. It is also mentioned on ni.com that there are alternative 'equivalent' certs that can be obtained from Microsoft, Novell, etc. Also mentioned that some independent courses maybe eligible but need to be sanctioned by NI first. I was wondering if anyone has taken any of the alternative routes and how it worked out for them.

Interesting...The closest I have come to functional programming is with Lua. I am not even sure it qualifies but have taken advantage of Lua's ability to assert a 'function string' that can be composed and executed at runtime. BTW, I really enjoyed the Spolsky article and am looking forward to your next post!

Yair - thanks for the reply. For now I have removed all VISA aliases and have not had a problem since.

Really good news! I would like to hear more about languages such as Erlang and other lightweight concurrent messaging concepts.

I have an application that opens 8 RS232 com ports with VISA aliases. I am finding that under various circumstances the VISA references are not being closed (even though I am issuing a VISA close) The problem is that when I try to reopen the com ports some seem to be still open thus giving the error that the resource is valid, but VISA cannot currently access it. I have tried closing the com ports before opening and even querying the VISA driver to see which com ports it thinks are open and then trying to close those ports. But nothing seems to be fool proof. Was wondering if anyone has come up with a solution for this, thanks.

Here is my take on converting Clusters to SQLite table records.... Cluster to SQLite Demo.zip

This guy really knows his stuff... www(dot)controlguru(dot)com I have found that understanding the open loop response of a system is a good first step. Try to use this knowledge to develop a FeedForward model of the system and then the PID portion will be able to deal with the smaller (and hopefully linear) error left over.

Anybody heard any word on this? I understand that it is forthcoming and that it will have some cool new features...

Yeah I should probably stay out of it but as the only electrical / software engineer on the team I was asked to make a suggestion. Really as you say it requires specialized knowledge. I like to be able to understand the root causes and fix the problem at the root rather than a bandage approach. Here in Florida (the lightning capitol of the world) surge damage is very serious concern. From what I have read, CAT5 surge protection should be done where cables come into the building and should be afforded a direct low resistance path to earth ground. The Telco's seemed to have solved this problem so I would be interested to understand their approach to grounding and surge protection.

Not really a LV question but regarding distributed systems installations... I have a large scale system that involve multibuilding LAN interconnects that is plagued by surge damage. From what I can gather, external (where cables come into the building) LAN surge protection and grounding is best. Does anyone have any equipment recommendations or guidelines on the subject? Thanks

Hi Dave - I thought your presentation was very good. Unlike many others I have seen you convey a sense of thoughtful composure and confidence in your subject material.

I think this will beat anything at NIWEEK...

Anyone seen the 2013 Device Driver DVD image yet?

I guess the broader topic here is how to store objects or complex data structures in a database. I think it should be possible to build a cluster to SQLite API but now that we have the lineator I wonder if it is possible and makes more sense to build this as a plugin.

Thanks all for the good comments. I am still unsure of a better way to construct a transactional data model that can be used by Multiple View Processes. Here is my take thus far: 1. Since the application requires Multiple View Processes I cannot pass around a class wire so will need interfaces to a central store 2. One of the nice things about the Model Class Data DVR is that you can extend the data model without breaking any wires directly connected to IPE's (I do not like that aesthetic either) or wrapping the IPE's in class methods and using the Get Ref vi in each case to extract the DVR onto the BD and into a local IPE. 3. The semaphore protection would be nice but seems complex to understand all nuances 4. A FGV housed Data Model solution by itself would be unwieldy since it is so limited in extensibility. 5. Will have to study the impact of data copies in my approach, thanks mje