I want to modify the trace expression of a trace I get for two voltage readings and one current reading when I do a DC sweep in OrCAD capture. The reason for this is that I want the data to be clearer when I export it to work with in excel. For example one of the traces is named V(D3:1,D3:2). I'd like to rename this to VR or something similar so that my excel data will be more understandable. However when I try to change the name in the "Trace Expression" box in the Modify Trace window I get an error that says ERROR(ORPROBE-3240): Invalid Expression(s). How can I solve this problem?