Hi!!, Please let me know if any code samples are available in VB to communicate with a modbus device. I am badly in need to communicate to a gas analyser supporing MODBUS RTU. Anybody pls, let me know the possibilities of getting the communication work. I tried with the MODTEST utility program and it works, but when i tried to send the same query using MSCOMM control in VB it doesnt work . what could be the problem ?