We are trying to communicate with a NHQ High Voltage unit via its RS232 port. We send (for instance) "U1 <CR><LF>" to determine the voltage on channel A. However, we are sent back (in ASCII) "U1<LF>????<CR><LF>". Many times we get a timeout error.
I suggest to send just U1<CR> without <LF>. After each such command there should be a waiting time of at least 200 msec before the next communication.
High Voltage Supplies