The plot button, available only in electrical mode, gathers input for a .plot line for inclusion in a SPICE deck generated with the deck command, or for immediate display after a SPICE run (with the run command) if the WRspice program is available.
The prompt area displays the command string as it is being built. Clicking on nodes or device ``hidden'' targets (usually indicated by a `+' symbol in the device schematic representation) will add hypertext entries to the command string, and will add a marker to the screen at the clicked-on location. One can click anywhere on a wire, or on subcircuit and device connection points to select nodes. Clicking on a marker will delete the marker, and the corresponding entry from the string.
Some devices have ``hidden'' nodes for accessing internal variables for plotting, such as the phase node of a Josephson junction. By convention, these are indicated with a `+' mark in the symbol. For most devices, this will access the current through the device. The marker for a current has an orientation in the direction of positive current flow. Ordinary node markers have no orientation, and access the node voltage.
Markers can be deleted by clicking on them, or by deleting the corresponding hypertext in the prompt line. Multiple markers can reference the same node, as long as they are spatially distinct.
The Enter key terminates entry, and creates the plot if WRspice is available. The command string can be edited in the usual way, thus functions of the variables, for example, can be plotted (but this syntax only applies to WRspice). In the deck command, the string will be added to the SPICE listing, when generated, as a .plot line.