comp.lang.idl-pvwave archive: archive » data acquisition, device control

Home » Public Forums » archive » data acquisition, device control

Show: Today's Messages :: Show Polls :: Message Navigator
E-mail to friend

data acquisition, device control [message #3406]

Thu, 26 January 1995 11:01

Richard Olsen
Messages: 10
Registered: November 1994

Junior Member

We'd like to use IDL as a front-end for data acquisition on a PC,
which basically means being able to talk to an A-D converter, and
presenting the results in ~real time with IDL

Has anyone done this, or something similar?

rc olsen
olsen@physics.nps.navy.mil

Report message to a moderator

Re: data acquisition, device control [message #3484 is a reply to message #3406]

Mon, 30 January 1995 09:01

Gary Kushner
Messages: 5
Registered: December 1994

Junior Member

Richard Olsen <olsen@physics.nps.navy.mil> wrote:
>
> We'd like to use IDL as a front-end for data acquisition on a PC,
> which basically means being able to talk to an A-D converter, and
> presenting the results in ~real time with IDL
>
> Has anyone done this, or something similar?
>
> rc olsen
> olsen@physics.nps.navy.mil

We have also been using IDL to control several devices in our lab.
We use the CALL_External function and have also used
the OUTPW and INPW(?) calls. The OUTPW and INPW calls allow
you to write and read ports and boards on a PC. You need to
know the base addresses of the boards you want to communicate to.

We use CALL_EXTERNAL to control our GPIB devices and to collect
data from a microchannel plate detector system. Our data acquisition
system consists of a National Instruments GPIB card and a National
Instruments digital I/O card. We wrote a windows dll that acts as
a "wrapper" for the GPIB functions provided by National Instruments.
For the digital I/O we required a fast data acquisition rate. We
wrote a windows dll to directly control the I/O card and to
collect the data. The dll then passes the data to IDL.

Dll's are not that difficult to write. Getting CALL_EXTERNAL
to talk to your dll can be a little tricky though.

The main problem we encountered was that a windows 3.1x dll can
only pass 64k of data at a time. Thus, if you wish to acquire
a large amount of data, you have to write your IDL code and your dll
to pass the data in small chunks or you could use interrupt
driven code. I am thinking of switching to Windows NT so that I can
have the process run under a different thread and so I can ignore
the 64k limit.

If anyone is interested, I can make available our IDL code and our
dll source code.

Report message to a moderator

Re: data acquisition, device control [message #3488 is a reply to message #3406]

Sat, 28 January 1995 13:28

rivers
Messages: 228
Registered: March 1991

Senior Member

In article <3g8rj4$smc@nps.navy.mil>, Richard Olsen <olsen@physics.nps.navy.mil> writes:
> We'd like to use IDL as a front-end for data acquisition on a PC,
> which basically means being able to talk to an A-D converter, and
> presenting the results in ~real time with IDL
>
> Has anyone done this, or something similar?
>
We do this in our projects at the National Synchrotron Light Source and many of
the experimental groups building x-ray beamlines at the Advanced Photon Source
at Argonne National Lab plan to use IDL as an important component of the
operator interface for data acquisition and display.

It is all done with CALL_EXTERNAL. Many of these projects have two "threads"
running. A real-time thread written in C handles the fast data acquisition and
interrupt handling. The IDL thread gets data from the C thread and displays it.
The IDL thread is widget driven and allows the operator to control the
acquisition, display and data storage.

____________________________________________________________
Mark Rivers (312) 702-2279 (office)
CARS (312) 702-9951 (secretary)
Univ. of Chicago (312) 702-5454 (FAX)
5640 S. Ellis Ave. (708) 922-0499 (home)
Chicago, IL 60637 rivers@cars3.uchicago.edu (Internet)

Report message to a moderator

Re: data acquisition, device control [message #3539 is a reply to message #3488]

Thu, 02 February 1995 10:18

kaaret
Messages: 7
Registered: June 1993

Junior Member

We do the same thing here at Columbia. We have a data input over a serial line.
The code to handle the serial line is in C and IDL gets the data via call external.
It works rather well. Writing the user interface in IDL is much easier than
writing an equivalent one in C.

Report message to a moderator

Previous Topic:	Re: Again.....plot interrupt?
Next Topic:	Re: Announcing PV-WAVE on Linux

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Wed Oct 08 13:38:29 PDT 2025

Total time taken to generate the page: 0.00769 seconds