2400 GPIB failing SCPI, passing 488.1

<p>I have two 2400 SMUs. I've set up a GPIB connection to them. If I have them configured for SCPI communication, an *IDN? query leads to a pair of error messages. First -201 (&quot;invalid while in local&quot;) and then -420 (&quot;query unterminated&quot;). The second error message makes sense because it was not expecting a query. I cannot understand why the first is occurring.</p> <p>If I switch the units from SCPI to 488.1 the *IDN? and other commands lead to the expected outcome. Any suggestions why I can't get them working with SCPI?</p> <p>I am testing with NI MAX and LabVIEW software on a Windows computer. I have a USB to GPIB adapter. There are several other instruments on the same bus that I am not encountering any problems with.</p> <p>UPDATE: I've continued to troubleshoot this issue, and it appears the root cause was the instrument getting into an error state and needing to receive a reset or clear command. The process of switching between SCPI and 488.1 was doing this, but that was not the fundamental problem occuring.</p>

This error you're experiencing could be related to one of two things: Either the preferred USB to GPIB adaptor requires 488.1, hence no error when you're sending SCPI commands over that protocol, or NI-MAX/LabVIEW is configured for 488.1 rather than SCPI.<br> The 2400 provides either 488.1 or SCPI as options depending on what your drivers/software/adaptors ask for.