TCP Connection Rejected

[MarLentz]

In an attempt to debug why my Hioki IM 3570 LCR meter was rejecting my TCP connection I came up with the attached piece of code. Does anybody have an idea why the "TCP Open Connection" is consistently rejected inside the innermost case, when it happily accepts the connection the three first times?

This snapshot was taken after single-stepping through the code, so it is not an issue of speed. Furthermore, I see the same behaviour if I remove the three outer connection attempts.

I'm confused.

Thanks

Martin

[MarLentz]

Nobody with an idea?

[wiebe@CARYA]

This problem is so close to the hardware, I don't think anyone will have an OoTB answer...

This should just work. If it doesn't, something is wrong. This could be wrong on any level; hardware, wiring, software, firmware. Without being able to toy around, even guessing is hard. In other words, can't really thing of anything.

Perhaps you need to connect through a specific address or port? Firewalls are off?

Perhaps toying with the advanced\specific VISA TCP\IP settings (No Packet Delay, HiSLIP)?

Wireshark might give some insight.

[MarLentz · Accepted solution]

Hi Wiebe

Thanks for the input. After some more playing around it turns out that LabVIEW somehow opens the VISA connection when asking for the connection type. Forcing LabVIEW to close the VISA connection (which I hadn't specifically opened) solved the issue - see attached. Apparently the instrument didn't like the open VISA connection when trying to communicate directly on TCP/IP