Hello,
I write an application to open two the same counters CNT-91 (Pendulum) to be connected to USB of one PC.
These counters have an identical USB VID, PID and are distinguished by Serial Number (SN).
But I can't open the counter using USB SN.
My app correctly sends and gets the NI VISA commands because I can open and control one CNT-91 using it's VID (VI_ATTR_MANF_ID==0x14EB) and get the SN.
Here are NI VISA used and correctly worked NI VISA functions, the status after execution and the SN in answer of CNT-91:
viOpenDefaultRM(@RM) : OK (Status=0)
SN1=PChar('USB?*INSTR{VI_ATTR_MANF_ID==0x14EB}')
viFindRsrc(RM, SN1, @findList, @numInstrs, Resource1) : OK
viOpen(RM, Resource1, 0, 0, @CNT1) : OK
viSetAttribute(CNT1, VI_ATTR_TMO_VALUE, 1000) : OK
viWrite(CNT1,'*IDN?\n',b,@RetCount) : OK
viRead(CNT1,buf,MAX_CNT,@RetCount) : OK
PENDULUM, CNT-91, 976722, V1.21 03 Dec 2007 :Result for '*IDN?\n' request, it contains the Serial Number 976722
viClose(CNT1) : OK
viClose(RM) : OK
The SN is 976722 in answer of CNT-91.
I also check this SN in Windows' Device Manager when connecting CNT-91 to USB.
But there are errors when I try to open the instrument using SN:
viOpenDefaultRM(@RM) : OK (Status=0)
SN1=PChar('USB?*RAW{VI_ATTR_USB_SERIAL_NUM==976722}')
viFindRsrc(RM, SN1, @findList, @numInstrs, Resource1) : VI_ERROR_RSRC_NFOUND (Status=0xBFFF0011)
In datasheet for CNT-91 the feasibility to use SN to open the instrument is proclaimed.
How one may correctly find and open the instrument using SN?
==
I also tried
SN1=PChar('USB?*INSTR{VI_ATTR_USB_SERIAL_NUM==976722}') //*INSTR vs *RAW
but with the same error.
I read the topic viFindRsrc using VI_ATTR_USB_SERIAL_NUM
but link in the second post for 'How do I Find All VISA Instrument Resources Using LabWindows?' is wrong.