Agilent 34401A multimeter to PC with Labview driver via RS232

[EvansL]

Attached are 34401A Error and 34401A DMM screenshot.

34401A connected to laptop via RS232 to USB(COM4).

[RavensFan]

Do your serial port settings match?  Do you have the right cable?

Is there a problem in your VI that we can't see because you didn't attach your code?

[EvansL]

Do your serial port settings match? 

Attached is Device Manager Serial Port settings and vi Serial Port settings. Both have similar values. It still prompt error.

Do you have the right cable?

Attached is USB to RS232 DB9 Mini Gender Changer.

Is there a problem in your VI that we can't see because you didn't attach your code?

I am using Agilent 34401 Read Single Measurement.vi that is default from LabVIEW.

[GerdW]

Hi Evans,

Attached is Device Manager Serial Port settings and vi Serial Port settings. Both have similar values. It still prompt error.

Well, the COM port in the device manager just shows its default settings.

That doesn't mean your device is using the very same settings!

So again: do you use the very same COM port settings as your DAQ device?

Your device is not responding according to the error message ("Timeout"). Does it even receive commands?

[EvansL]

do you use the very same COM port settings as your DAQ device?

Since you mentioned "doesn't mean your device is using the very same settings!", can you kindly guide me in clear steps to change the 34401A port settings.

Your device is not responding according to the error message ("Timeout"). Does it even receive commands?

Can you kindly guide me the steps to check if it receive commands

[GerdW]

Hi Evans,

can you kindly guide me in clear steps to change the 34401A port settings.

There should be a separate chapter in your manual for that device. Just read it!

Can you kindly guide me the steps to check if it receive commands

Most often such DMMs have a display showing the current settings.

When you send a command to change a setting you will see that change in the display too.

So does the display change when you send a command?

[EvansL]

So does the display change when you send a command?

Definitely no display change between LabVIEW and 34401A.

Problem could possibly be mini gender changer.

Null modem should be use, not mini gender changer.

Source: https://forums.ni.com/t5/LabVIEW/RS232-to-USB-with-Agilent-34401A-and-E3631A/td-p/3546010

[RavensFan]

If you need to use a gender bender in order to get the cable to physically plug into the port on the DMM, that is a pretty strong indication that the DMM is not behaving as a DTE device but a DCE device.  If you read the manual, it should tell you whether or not you need a null modem cable.  (they would usually have female connectors on both ends since they are designed to connect two DCE devices, like PC's, where they would have male ports (pins), on the device.