Process scheduler architecture

[pgaastra]

Hi all,

I’m struggling with Google trying to get some ideas for the architecture of a LabVIEW program which will inject up to 28 chambers with a gas for a time (different for each chamber)  one after the other,  let them sit for a time (different for each chamber) and then purge for a time.

So far we have the idea of having a task queue.  It starts with getting the first container parameters to put tasks into the queue.  As it is processing the tasks for this first container it will come to the “End of injection” task which will cause the next chamber’s tasks to be put into the queue (some requiring insertion between some of the tasks of the first chamber). Etc etc.

I am not asking anyone to write the program for us but can you point out anything on the web which might help? One of the problems with Googling is that all the keywords have a lot alternative uses for them.

[SteveChandler]

I hate to ask something that might be obvious. Have you looked at using a state machine?

[pgaastra]

Thanks Steve,

I had thought about using a state machine but to my way of thinking it's just going through a list of tasks which gets bigger as more chambers are involved and then dwindles away to none when the final chamber is finished.  Not really any well defined states.  I probably am looking at it the wrong way.

I suppose I could have a state machine for each chamber.  Each chamber's state machine spawns another state machine when the time comes for the next chamber to start.

What do you think?

[SteveChandler]

What is your experience level with LabVIEW? Specifically are you comfortable with LVOOP? I am investigating the Actor Framework for something similar>

[pgaastra]

Hi Steve,

You have exposed the reason why I did this post.  I have used labVIEW since about 1992 but only ever once or twice a year to do some simple low level stuff.  A National Instruments guru/salesman once visited me and said I program like they did five years ago.

I have never even looked at LVOOP.  I once did an introductory C++ object oriented course but I never got to use the stuff so I struggled with the concepts.

I'll have a look at this Actor Framework but I think it will require too much of a learning curve.

Thanks

[SteveChandler]

There is a learning curve with the Actor Framework. It might not be the right solution for you simply for that reason.

If you want to pursue OOP You should get a copy of The Object Oriented Thought Process. It is a very good book and is only just over one hundred pages. Very clear and to the point.

As for LVOOP just keep this in mind. An object is really just a type defined cluster and a collection of VIs that have permission to bundle and unbundle from that cluster. There is a lot of fancy things you can do such as inheritance and dynamic dispatching. You don't need those things to successfully use LVOOP though.

[pgaastra]

Thanks again Steve,

Yes, I had a look at the Actor Framework power point presentation and it would be a huge learning curve.  Unfortunately the user wants the program yesterday.   

This has been interesting.  I'll put that "The Object Oriented Though Process" on my list of books to get.

I think I'll stick with the queue of tasks for now.

Thanks