Looking for a vb guru

[chakorules]

I am using an Acuity Visionscape Express Vision System board in an NT 4.0 SP6 box. I am not a VB guru by no means, but here is what I am trying to do.

The Vision board comes with some standard Active X controls which are pretty slick. One of the calls is I can read and write to a "virtual I/O" point. I'd like to monitor an OUTPUT from one of these virtual I/O points to trigger an event in my own VB code.

Trouble is, since VB is event driven, the virtual I/O point on the vision board is not driven by a user, but rather the board itself.

So my question is, is there an VB events or controls I can use that can monitor another Active X control for change of state?

Here was my two thoughts:

1. Make an event triggered timer, this would act as a "heartbeat" I assume. After each timer expire, run the subroutine to "read" what the state of the virtual I/O point is on the vision board. This would work, but I'd rather trigger an event on change of state from the virutal I/O point.

2. Somehow read the virtual I/O point in "realtime" to a lblMyVirtualPoint.Caption. Then use the event On_Change to trigger my change of state subrountine.

Any thoughts or suggestion? Or pointers in the direction along the lines of some control or active x component I can use to monitor or do some "realtime" monitoring? Chris Elston
Automation & Controls Engineer

http://www.mrplc.com

Download Sample PLC Ladder Logic Code
at MrPLC.com

 

[HunterGA]

Look for a callback function. The software/controls for the board will probably have one. If so, you can use teh Win32 API to "point" the callback stub to a procedure in your code. The callback is real-time and is independant of any user interface you build. You should put the callback functions in a class module and add it to your project. If you cannot find info on a callback function in the board's documentation, I would call the vendor for help.