Experimental Physics and
Industrial Control System

Mark Rivers <[email protected]> · Tue, 3 Nov 1998 8:37:47 -0600

> 	I want to use a frame grabber on a PC running Linux. To link such
> a system to an EPICS world I have to write a portable channel access. 

You may not need to use the portable channel access server for your task, you
may be able to simply use the channel access client.  It really depends what
you want to do.

For example, I have a CCD camera controller in a PC running Windows NT.  I
need to take a frame with this camera and save it to the local PC disk during
a scan which is controlled by EPICS in an IOC.  The way I do this is just to
have a soft binary record in the IOC.  The EPICS system in the IOC sets this
flag to 1 when it wants a CCD frame taken, and waits for the flag to go back 
to 0 before continuing.  A very simple Visual Basic task in the PC just waits
for that flag to go to 1; when it does it calls the CCD software to take a
frame, and once the frame is safely on disk sets the flag back to 0.  This is
all done using channel access client rather than channel access server.

> I would also appreciate any hint about frame grabbers plugged in PC or on
> any other platform to find the best solution.

We are using lots of Princeton Instruments CCD camera controllers (more
sophisicated than frame grabbers) on PCs under Windows NT.  The software is
very nice: Princeton Instruments utilizes Microsoft's COM (Component Object
Model) interface.  The COM model exposes all of the functionality of their GUI
data collection program as objects which can be accessed from any COM
compliant application, such as Visual Basic, Visual C++, Excel, etc.  Thus the
user can set up the camera using their GUI program.  Once it is set up a very
short (1 page) Visual Basic program can be used as the "daemon" described
above.
____________________________________________________________
Mark Rivers                             (773) 702-2279 (office)
Argonne National Laboratory             (630) 252-0422 (office)
Building 434A                           (630) 252-0405 (lab)
9700 South Cass Avenue                  (630) 252-1713 (beamline)
Argonne, IL 60439                       (630) 252-0443 (FAX)

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System