Modscan32

ModScan32 is a Windows shareware application which operates as a MODBUS master. It allows you to access and change data points in a connected slave device using either the RTU or ASCII Transmission mode. ModScan32 is ideally suited for quick and easy compliance testing of the MODBUS protocol and its built-in display of serial traffic allows effective troubleshooting of field connections.

Download here - http://www.bb-elec.com/bb-elec/software/modscan/modscan32.zip