problems in Labview communication with Agilent E3649A power supply through RS 232

[Adriana_Angelotti]

I'm using Labview 2012 to interact with Agilent E3649A power supply via RS 232.
I installed the agilent E364XA series drivers for Labview 8.5.
The code is made to set the supply voltage and measure voltage and current.
The problem is that often I get the error "1073807339" at VISA read, stating "timeout expired". Sometimes the error happens at the very beginning, after the Initialise, and sometimes it occurs at the "measure" step. The strange thing is that sometimes everything works without any error.
By using NI-MAX I can see the instrument and also increase the instrument timeout ( I tried 10 s, the default is 2 s), but the latter does not seem to be the problem indeed.
Any suggestion will be really appreciated!

[RTSLVU]

Most issues with serial communications can be solved by watching this video: VIWeek 2020/Proper way to communicate over serial

[crossrulz]

Earlier this year, I was working with a similar power supply (a triple output supply instead of a dual, but still the same family).  I found that the supply was sometimes horribly slow at reacting to commands and so its buffer would fill up.  Once that happened, nothing was getting through to that supply.  So I ended up adding a "*OPC?" after each command to wait for it to complete that command before I then went on to the next one.

[Adriana_Angelotti]

Hello Crossrulz,

thank you for your suggestion, but I'm not able to implement this basic communication with the instrument in Labview. Actually I'm using predesigned sub vi to communicate with the Agilent power supply.

Today I tried another way, namely using GPIB/USB interface rather than RS 232 and everything works perfectly. So I will move to this interface. Thanks