Calling LabView ActiveX Server from TCL?

Question

Does anyone have experience calling a LabView ActiveX server vi from
TCL? I created a simple VI with one control (labeled "A") and one
indicator (labeled "B") and a +1 adder between them. I can load and
open the VI from TCL:
package require tcom
set lv [::tcom::ref createobject "LabView.Application"]
set viPath "D:\\National Instruments\\LabView\\Activity\\a.vi"
set vi [$lv GetVIReference $viPath]
$vi FPWinOpen True
But when I try to send in data:
$vi -namedarg Call A 1
I get the error message "unknown parameter A".
I have also attempted to duplicate the "ActiveX Server" example
from the LabView help file, calling "Frequency Response.vi". This
approach encounters the same error message:
% package require t
com
3.0
% set lv [::tcom::ref createobject "LabView.Application"]
::tcom::handle0x013202F4
% set viPath "D:\\National
Instruments\\LabView\\examples\\apps\\freqresp.llb\\frequency
Response.vi"
D:\National Instruments\LabView\examples\apps\freqresp.llb\frequency
Response.vi
% set vi [$lv GetVIReference $viPath]
::tcom::handle0x01335AE8
% $vi FPWinOpen True
% $vi -namedarg Call Amplitude 10
unknown parameter Amplitude
If anyone can point me in the right direction, or give me an
example of how to do this I would greatly appreciate it.
TIA.
Leslie

Answer 1

In article ,
Leslie Brooks wrote:
>"Bruce Hartweg" wrote in message
>news:...
>> "Chin Huang" wrote in message
>news:[email protected]...
>> >
>> > I don't use LabView, but from the Visual Basic example I saw, it seems
>> > the Call method takes two arguments. The first is an array of parameter
>> > names and the second is an array of parameter values. Try to send in
>> > data with the Tcl command
>> >
>> > $vi Call [list A] [list 1]
>>
>> I'm unable to help the original question (don't know LAbView or VB stuff) but
>> just want to point out that [list A] is equal to A and [list 1] is the
>same as 1.
>>
>> Bruce
>
> I know what is supposed to be passed to the 'Call' method. Doing
>this:
>
>set inst [::tcom::info interface $vi]
>$inst methods
>
> produces (among other things):
>
>{1015 VOID Call {{{in out} {VARIANT *} paramNames} {{in out} {VARIANT
>*} paramVals}}}
>
> So the 'Call' method is expecting two parameters, both pointers
>to variants. TCOM appears to be passing the correct parameter type
>because the TCOM documentation says that a TCL List maps to a
>one-dimensional array of VT_VARIANT. However, the results are
>INvariant (bad pun intended):
>
>% $vi -namedarg Call Amplitude 10
>unknown parameter Amplitude
>% $vi -namedarg Call [list Amplitude] [list 10]
>unknown parameter Amplitude
>% $vi -namedarg Call [list Amplitude] [list [::tcom::na]]
>unknown parameter Amplitude
>% set i 5
>5
>% $vi -namedarg Call [list Amplitude] {incr i}
>unknown parameter Amplitude
>% $vi -namedarg Call [list Amplitude] [list [incr i]]
>unknown parameter Amplitude
>% $vi -namedarg Call Amplitude [incr i]
>unknown parameter Amplitude
>
> Who can help me with this? Who is the LabView Guru?
Try invoking the Call method without the -namedarg option. The
-namedarg option doesn't work the way you seem to think it works. The
-namedarg option provides a way to specify arguments named from the
method's parameter specification. For example, you discovered that the
Call method take two parameters named "paramNames" and "paramVals".
Tcom returns the error "unknown parameter Amplitude" because "Amplitude"
doesn't match either parameter name.