looking for advice on project

[Wolleee]

Hi all,

Im looking for advice on a project im going to start soon.

Information on project:

im going to have a computer setup on say the otherside of the building which is going to be connected to a relay board to toggle the relay.  I have to have  a computer setup to talk to the relay board.  I want to be able to toggle the relay from my computer, say over the network, and it is possible that there could be as many as 5 people trying to toggle the same relay.

Any thoughts or advice on how i might go about this?

THanks,

Matt

[RavensFan · Accepted solution]

I'd use network shared variables.

The only question I have is how do you keep 5 different people from operating the relay at the same time?  Or someone says turn on while another says turn off.  How do you arbritrate that?  Who wins?  Or does each need to wait their turn?

But you can certainly do what you want.

[Wolleee]

Hi ravens fan,

ive played around with shared netowork variable, but have never got anything to work.Ill obviously have to figure out something to give control of the relay to one person at a time, but i think i can figure that out.  I have read some of the white papers and examples, but still with no luck.  Do you have a simple example in 2011 that i could test to simply toggle a boolean indicator or something?

Thank you,

Matt

[natasftw]

If the white papers don't help, an example won't either.

You're running into network issues or you haven't deployed the shared variables.  A simple example is something you can create from those white papers.  Do you see your variable using the Distributed System Manager on the PC that's hosting the variable?

[PatrickLye]

I've found that network shared variables work very well on a good network, but if you have a poorly managed network, like our companies office network, they don't work well at all. This is a problem with the network, not the shared variables. For this office network I've started using an SQL database server for communication or network streams with a connect/reconnect state machine that I wrote. On my pristine industrial network the machinery runs very well with shared variables.

This might help:

http://digital.ni.com/public.nsf/allkb/6E37AC5435E44F9F862570D2005FEF25

AND

If you can, turn off your firewalls to see if you get communications, but if this helps, depending on your network security, you may need to turn them back on and configure them to pass the shared variables.

AND

The following is from an older blog posting by Michael Hirsch. I can't locate the link any longer.

Windows 7x64 Firewall

These must pass through the firewall:

c:\windows\SysWOW64\lkads.exe

C:\Windows\SysWOW64\lktsrv.exe

C:\Program Files (x85)\National Instruments\Shared\Tagger\tagsrv.exe

note: for Labview 32-bit, the lkads.exe and lktsrv.exe will be under c:\windows\system32\

Also you must allow the following ports through windows firewall:

TCP: 2343, 59110-59115

UDP: 2343, 6000-6010

For TCP ports, you must open one port above 59110 "per application," by opening 59110-59115 we assume that no more than 5 applications are running concurrently.

[Wolleee]

Thanks for the tips patrick,

Before i go troubleshooting everything it could be something simple i dont understand.  I have my variable set up with enable aliasing on.  Now on my server and client, using the deployed shared variable manager, i can see that the variable is deployed, reading the same value, and has the same time stamp. 

Problem now is that i cant change the value of the variable not through the application or thought the manager. 

Any clues?

[Wolleee]

Hi all,

Just got the variable working.  I was unable to write to the variable because i had deployed it on 2 computers, enabled aliasing on both. 

Thank you for all your help.