The GPIB Device and Controller functions listed in the GPIB Misc function description are described here. Notice that there are both device and controller versions of the ppc and loc commands. The syntax and use of the commands are slightly different for each version.
You can use these functions with all GPIB Controllers accessible by LabVIEW unless stated otherwise in the function description. An ECMD error (17) results when you execute a function for a GPIB Controller without the specified capability. The function syntax is strict. Each function recognizes only lowercase characters and allows only one space between the function name and the arguments.