Modbus Software
- Modscan32: General purpose Modbus monitoring software
- SimplyModbus: General purpose Modbus monitoring software
- PortMon: Windows serial communication monitoring software - debug only, not for general purpose use.
- Modbus Tester: - free, very simple test program. Also called "MTester". This only works with COM1 - COM4, so it won't work with most USB RS485 interfaces, which tend to use higher COM port numbers.
- Ocean Controls ISEE Modbus
- ModbusPoll: http://www.modbustools.com/modbus_poll.asp
- PvBrowser: http://pvbrowser.de/pvbrowser/index.php - Open source with graphing; supports many protocols in addition to Modbus TCP. Has a code generator for creating servers.
- CAS Modbus Scanner: Free, debug only, supports both Serial RTU and Modbus TCP
