Visa Driver Error -1073807202

[Minions]

Can you attach the NI-Max communications with the instrument along with the port configuration for your instrument in NI-Max?

[FischerM16]

Hi,

this communicaton was performed with NI MAX with a Microwave Synthesizer. 

1: Write Operation (*IDN?\n)

Return Count: 6 bytes

2: Read Operation

Return Count: 47 bytes

Phase\sMatrix,FSW-0020,00000108,1330100248,0100\n

I can also read the current device temperature (after translation of the hex code "00D7": 21,5°C):

3: Write Operation (10)

Return Count: 2 bytes

4: Read Operation

Return Count: 5 bytes

00D7\n

I can even switch on the RF output which I can confirm as my MW power detecting diode shows me a jump in voltage:

5: Write Operation (0F01)

Return Count: 4 bytes

For the fiber thermometer it is very similar: similar communication, correct answers, but same VISA Error -1073807202.

Communication standard specified by the manufacturer: 

This port is USB 2.0 compatible and is utilized as a standard COM port (serial port) on the host PC. The serial data buffer for this port is 64-bytes long (including the terminator); thus, it is important not to exceed this length on any command data. All commands must be terminated by a termination character (13, 0X0D). The serial port parameters on the host PC must be set as 8 bits, no parity, 1 stop bit, 115200 baud, no flow control.

I have attached a picture of my NI MAX configurations (sorry for German language in MAX). 

I'm still absolutely clueless why communication via MAX works, but not with a LabVIEW VI...

WBR

[Albert.Geven]

can you also send the .vi?

[Minions]

In NI-Max, you show the interface  as COM5 while in your code you have it entered as COM4.

[FischerM16]

Hello everyone,

in the mean time I found the solution to my problem: Even though my system is set up as a 64bit Windows, I should use LabVIEW in the 32bit variant. 
Now I can communicate properly and build VIs as I need them. For my understanding, do you have an idea why I can't use 64bit LabVIEW? Did anybody else notice this before?

Thank you very much for your help!