I searched the forum and found only a thread on returning to local mode programmatically for the 34410A DMM. (which was DIAG:LOCAL). However, I tried that with the 34401A DMM and it doesn't work. I looked through the user's guide, and it only mentions returning to local mode when in serial mode only. (i.e. SYST:LOCAL). Essentially, I am using a gpib interface to the 34401A DMM that I want to take a measurement via scpi commands and then return the DMM unit back to local mode wihtout having to press the 'Local' key on the DMM. If someone can provide the appropriate scpi command to do this for the 34401A DMM, that would be greatly appreciated.
The 34401A does not have a built in SCPI command to control remote and local. You will have to use a lower level GPIB command related to te REN line in order to do this. What programming environment are you using? VB, C, Matlab, Labview, etc...? If you let me know which one, I can try and assist you with the correct command.
I'm using C# programming language to send commands to the 34401A in scpi command format. I am connecting to it using its VISA address that is found from the Agilent Connection Expert. I normally test out the commands I'm going to send to the instrument by using the Agilent Interactive IO dialog window. Let me know if you need more information.
Both the 34401A and 34410A DMMs remote and local modes can be controlled by the VISA function viGpibControlREN(). The function takes two arguments, the first the handler for the instrument returned by viOpen, the second a predefined attribute found in the VISA library. The attribute VI_GPIB_REN_ADDRESS_GTL will return front panel functionality by sending the "go to local command". The attribute VI_GPIB_REN_ASSERT_ADDRESS_LLO will lock the front panel and place the device in the remote state by sending the Local Lockout command.
C# Agilent VISA Library Example
//Send Instrument into Local Mode
//Send Instrument into Remote Mode
Please note that these commands will not remote/local any VISA GPIB device. Also, many instruments automatically go into a remote state when a connection is opened or IO is performed. Please refer to Agilent VISA help on this function for additional information.