The commands for TDR measurement (Option TDR) should be sent via SICL-LAN through TCPIP0::localhost::inst0::INSTR address. The TDR application must be installed and executed on your PC before you send the TDR commands. These commands can not be used in the built-in VBA.
The Command Finder helps you to find the command.
The TDR Notation Convention helps you understand the commands.