The floating point number 3.4e38 has special meaning for programmers writing DLLs that the NeuroShell Trader calls. It is the value that you return when you don’t want to plot anything on the chart at that bar. It is also the value you will find in inputs when the input is missing at that bar.
For more information on coding DLLs that the Trader can call, see the SDK in the “New and Updated Examples” section of this web site. The examples there are in C, but there are plenty of PowerBasic examples in the same section, and even one in Delphi.