# Modbus TCP Communications

Modbus TCP is a client/server protocol originally developed by Modicon for industrial automation systems. It is one of the oldest industry standard methods for the transfer of information and register data between industrial controls and monitoring field devices.

## Modbus TCP Commands

Note: For more information on this Modbus TCP implementation, see Modbus TCP Factory Interface.

Code | Description | Address Space
--- | --- | ---
0x01 | Read Coils: Reads the state of 1 to 2000 contiguous coils in a remote device. This command can be used by a PLC to read data from the vision system. | Coil
0x05 | Write Single Coil: Writes a single output coil to either ON or OFF in a remote device. This command can be used by a PLC to write data to the vision system. | Coil
0x0F | Write Multiple Coils: Writes a sequence of 1 to 1968 coils to either ON or OFF in a remote device. This command can be used by a PLC to write data to the vision system. | Coil
0x02 | Read Discrete Inputs: Reads the state of 1 to 2000 contiguous discrete inputs in a remote device. This command can be used by a PLC to read data from the vision system. | Discrete Input
0x03 | Read Holding Registers: Reads the contents of a contiguous block of 1 to 125 holding registers in a remote device. This command canbe used by a PLC to read data from the vision system. | Holding Register
0x10 | Write Multiple Registers: Writes from 1 to 123 contiguous registers in a remote device. This command can be used by a PLC to write data to the vision system. | Holding Register
0x04 | Read Input Registers: Reads from 1 to 125 contiguous input registers in a remote device. This command can be used by a PLC to read data from the vision system. | Input Register