Siglent Strange VISA Behavior

[Andrew_F]

Just a note on that last post.  I'm looking through the VISA specification and I see that viOpenDefaultRM() is actually a call to the VISA system itself.  So, I'm back to being confused again.  Where is the session to the instrument being opened OR closed?  I see these events when calling the VISA open and close vi's explicitly, but not when I ignore them.

[ben64]

Have you tried setting the VISA class to USB Instr? By default the VISA class is Instr, to change it right click the VISA resource name control and select VISA class ->  I/O Session -> USB Instr.

When you only use the VISA Write do you observe multiple open VISA session (by clicking on the down arrow at the right of the VISA resource name control)?

Ben64

[MrJackHamilton]

I can say it's 2020 using LabVIEW 2019 SP1 and am seeing this exact behavior with Siglent devices and even BK precision devices using the 'IVI' what is criminal is the IVI driver issue date is 2013 which is quite old and long before Windows 10.

I am very conversant with Serial, VISA and TCP/IP and this behavior is odd, bizzare and needs to be corrected at the low-level driver level.

Using this 'IVI' device, it does not appear as a COM port but under the Device manager tree as "IVI' Instrument/Device. You can't use 'Bytes' at port to perform a VISA read operation - you can only do a VISA Write - then a VISA Read with a idiotic timeout, and huge bytes to read - which cause a terrible long delay before the data is returned.

The siglent VISA drivers appear written well and simple...but they simply don't work...but it;s not the LabVIEW driver level IMO. Consistenly, performing VISA write/read operations will result a complete loss of the VISA device reference. The error message is catastrohic ' Device or resourse is not avaiable / found.: Meaning the IVI driver has left the building...

You have to unplug or power cycle the instrument to recover from this. When this happens, the instrument is running, not locked-up, or displaying any behavior equating to a complete loss of it's existence on the IVI port.

It's a frustrating mess. They should simply connect, communicate and work. I have not tried the TCP/IP, but am not optomistic. Also siglent does not have direct tech support, and what troubleshooting they do suggest consists or 'is it plugged in...do you have a bad cable..".. BS.