in NI max, VISA query can work, but write /read not

I am using VISA test panel in NI max to send "*IDN?\n" to a Handler. when  click "query" button, i can get response string "Hontek". but instead if i first click "write" then click "read", there is an error shows( 0xBFFF0015 Timeout expired before operation completed). through IO trace, i saw that "query" also send "write/read" command, so what's the different?

in my VB code, i am using write/read function to communication with instrument and it not work. how could i fix it?

Thanks again

Peter