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Modbus Tool

Modbus is an industry standard protocol for communication between a master unit and one or more slave devices.

The Modbus Tool has the following features:

  • RTU, ASCII and TCP mode supported.
  • Both master- and slave- mode supported.
  • Simple slave device can be simulated directly from script.
  • Advanced slave devices can be supported by writing a simple plug-in. Examples are supported.

 

Master Mode

The master tool has methods for the following protocol commands (function codes):

  • Read Coils (1)
  • Read Discrete Inputs (2)
  • Read Holding Registers (3)
  • Read Input Register (4)
  • Write Single Coil (5)
  • Write Single Register (6)
  • Write Multiple Coils (15)
  • Write Multiple Registers (16)

 

Slave Mode 

Slave tools have a register database used to contain the register values both written by the master and to be returned when read by the master. That makes the communication with the master independent of the test script execution.

The slave tool has methods to get and set the values in the register database.