Thank you all for the help...just one more thing...i have a labview code to ask the serial number from the pump but i cant have any response...i think its because the response time of the pump...can anyone give me some ideas of where is the problem? if needed i send the labiew code...By the way, i am using a rs232 to usb cable, it works in this case, or i need to use a pure rs232 cable?
