LabVIEW to control a PLC

[csjasnoch]

So on the NI website there is a lot of white papers talking about how
it is easy to integrate LabVIEW into an existing control system. I
have yet to see anything good examples of this though.
I am wondering if anyone out there has used LabVIEW as a build on to
an existing control system using mainstream PLCs such as GE 90-30s or
VIPA (Siemens) or AB.
Then were you able to remove out the standard ladder logic program and
use the PLC as a central control for the I/O and thus have LabVIEW do
the thinking, be it in a PC or an embedded controller.

[Brian_Beal]

That really misses the point of a PLC.  Either you have a PLC that is in control, and have Labview in a more supervisory role, or have Labview control field I/O, and a field processor would not be needed.

[RDR]

Here is a customer solution:

I2S Uses CompactRIO to Optimize PLC Automation in Steel Rolling Mills

Is this what you are looking for?  If you would like assistance with any of this, please give us a call!  Have a great afternoon.

-Bob

[tst]

We have done several systems like this and the key point is to only do this where it is applicable - Windows is not a real-time operating system and TCP is not a deterministic protocol, so this can only be used for systems where you don't need great speed (10-20 Hz is reasonable, although you can do more) and where you don't mind the possibility of occasional failure (although my experience is that XP is very stable when handled properly).

The actual interaction with the PLC can be done either by using OPC or by writing VIs which will use whichever protocol the PLC supports (e.g. Modbus or a proprietary protocol).

For those wondering, the two main advantages are saving money, either on buying cheaper hardware, not replacing existing hardware or reducing development time and ease of use - debugging and changing a LabVIEW program is much easier.

Message Edited by tst on 10-13-2007 08:45 PM