I'm not familiar with this 'measure' program, but to send a serial command and read back a result you do indeed need to use a VISA Write followed by a VISA Read. Depending on how the data you are expecting back is formatted, you may want to read a fixed number of characters, to make use of VISA's termination character property, or to insert a delay between writing and reading.
You'll need to give more explanation of your 'trouble with the space character' in order for anyone to offer constructive advice...