I have a program which sends text to an LED sign.
prismcom.exe
To use the program to send \"Hello\":
prismcom.exe usb Hello
You can also run exactly same command at Cmd.exe command-line using PowerShell. I'd go with this approach for simplicity...
C:\>PowerShell -Command "temperature | prismcom.exe usb"
Please read up on Understanding the Windows PowerShell Pipeline
You can also type in C:\>PowerShell at the command-line and it'll put you in PS C:\> mode instanctly, where you can directly start writing PS.