Winmodbus Master can communicate over TCP/IP or Serial.

From the main menu, select [Comms Parameters] from the [Setup] menu and you should see a dialog allowing you to define the comms channel to the modbus slave.


IP address and port should be defined. You can also use a hostname in place of the ip address.


Choose from one of the available COM ports listed and set serial parameters. Ensure the same Baud rate as the Slave is using. Parity is usually None and Stop Bits is usually 1.

Protocol & Timings

The protocol can be Modbus TCP (includes a 6 byte header) or Modbus RTU (No header. 2 byte CRC on the end).

You must specify a modbus address to poll for and this should correspond to the address of the slave you are connected to.

The Poll Rate is used when performing multiple polls (From the Run command) and will be the time waited after receiving a reply until the next poll is issued

The Timout is the number of millliseconds waited for a reply after a poll is issued before giving up and either retrying or going on to the next poll.

The Retries specifies how may times a poll should be issued if it is timing out before giving up.