The Modbus port tool driver provides the means to set RTU serial bus parameters and directly read / write to devices connected via RTU (serial bus) or TCP (Ethernet).
Modbus/RTU data rate (BAUD rate) - The speed of the bus can be set or changed to align with the devices connected to the Modbus RTU port. The drop-down menu list all seven speeds defined by the Modbus.org specifications (1200 to 115200 bps).
Modbus/RTU parity - Three “Parity” options are offered in the drop-down menu (No parity, Even parity , Odd parity).
To apply the diagnostic settings it is not necessary the “Save changes”, simply click the associated “Set” button.
Monitor address - Enter the device I.D. (Modbus address) of the connected device you wish to read and or write to and click “Set”. If using TCP, the address is the last octet of the device's IP address.
Monitor port - The drop-down menu selections are; Monitor off, Modbus RTU or Modbus TCP. Make the selection and click “Set”. When not in use set to “Monitor off”.
If using another driver as the primary means of setting the RTU baud rate and parity (ezeio System info, Standard I/O, Advanced I/O), the settings must align. Conflicting settings may effect the RTU communication.
Two registers can be monitored live, on the right hand panel under “Available registers”, allowing users to see changes made via “Direct write”. The registers can also be logged by adding to to Fields.
Monitor register 1 & 2 - Enter the register addresses you wish to monitor and click “Set”
Register type - For each of the registers, set the type and click the “Set” button. The drop-down menu offerings are listed in the table below. Refer to the devices documentation and Modbus register map for the register type for each specific register
| Type (abbreviated) | Description |
| INT16/HLD | Holding register, 16 bit integer |
| UINT16/HLD | Holding register, 16 bit unsigned integer |
| INT32/HLD | Holding register, 32 bit integer |
| INT32 Big Endian/HLD | Holding register, 32 bit integer w/ More significant byte sent first |
| FLOAT/HLD | Holding register, 32 bit Float |
| FLOAT Big Endian/HLD | Holding register, 32 bit Float, w/ Mort significant byte first |
| INT16/INP | Input register, 16 bit integer |
| UINT16/INP | Input register, 16 bit unsigned integer |
| INT32/INP | Input register, 32 bit integer |
| INT32 Big Endian/INP | Input register, 32 bit integer w/ More significant byte sent first |
| FLOAT/INP | Input register, 32 bit Float |
| FLOAT Big Endian/INP | Input register, 32 bit Float, w/ Mort significant byte first |
Write register - Enter the address for the register of which you wish to modify the value and click “Set”.
Value - Enter the new value to be written and click the associated “Write” button