Closes a VISA connection to an Instrument/Device
#include <Visa.au3>
_viClose ( $hSession )
| $hSession | A VISA session handle as returned by _viOpen() |
| Success: | 0. |
| Failure: | -1 if the VISA DLL could not be open or a NON ZERO value representing the VISA error code (see the VISA programmer's guide). |
As for all the VISA functions the VISA libraries must be installed (you can check whether visa32.dll is in {WINDOWS}\system32) and a GPIB card (such as a National Instruments NI PCI-GPIB card or an Agilent 82350B PCI High-Performance GPIB card) must be installed
_viExecCommand, _viFindGpib, _viGpibBusReset, _viGTL, _viOpen, _viSetAttribute, _viSetTimeout
; - This assumes that you have instrument set to GPIB address 1
; It shows how to use the _viExecCommand function in stand alone mode and combined
; with _viOpen and _viClose.
; It also shows the _viGTL function
#include <MsgBoxConstants.au3>
#include <Visa.au3>
Local $h_Session = 0
; Query the ID of the instrument in GPIB address 3
MsgBox($MB_SYSTEMMODAL, "Step 1", "Open the instrument connection with _viOpen")
Local $h_Instr = _viOpen("GPIB::3::0")
MsgBox($MB_SYSTEMMODAL, "Instrument Handle obtained", "$h_Instr = " & $h_Instr) ; Show the Session Handle
; Query the instrument
MsgBox($MB_SYSTEMMODAL, "Step 2", "Query the instrument using the VISA instrument handle")
Local $s_Answer = _viExecCommand($h_Instr, "*IDN?") ; $h_Instr is NOT A STRING now!
MsgBox($MB_SYSTEMMODAL, "GPIB QUERY result", $s_Answer) ; Show the answer
; Query again. There is no need to OPEN the link again
MsgBox($MB_SYSTEMMODAL, "Step 3", "Query again. There is no need to OPEN the link again")
$s_Answer = _viExecCommand($h_Instr, "*IDN?")
MsgBox($MB_SYSTEMMODAL, "GPIB QUERY result", $s_Answer) ; Show the answer
MsgBox($MB_SYSTEMMODAL, "Step 4", "Close the instrument connection using _viClose")
_viClose($h_Instr) ; Close the instrument connection