2 Operation 2-4-2 Modbus TCP Master/Client Applications The CP1W-MODTCP61 allows Omron CP1L and CP1H PLCs to function as control devices for remote I/O slaves that use the Modbus TCP protocol. The adapter is a Modbus TCP master device, meaning the adapter will not respond to Modbus TCP commands issued from another Modbus TCP master device. The Easy Modbus function of the PLC is used to send Modbus RTU commands to the adapter, which are converted to Modbus TCP commands and delivered to the remote device.
The Modbus RTU Node Number is automatically used as the last octet of the IP address of the destination device, with the first 3 octets of IP address of the adapter used as the first 3 octets of the destination device. Example The CP1W-MODTCP61 Adapter IP address is set as 192.168.1.25. A Modbus RTU command sent to node ‘2C’ in the PLC using Easy Modbus. The Modbus TCP command will be delivered to 192.168.1.44 (44 Decimal = 2C Hex). Additional Information • Disconnected slave nodes will cause timeouts in the PLC Easy Modbus function, slowing the update to the remaining nodes.
• Unlike the Modbus TCP Slave/Server mode, the FINS protocol is not available when using the adapter as a Modbus TC P Master/Client. If an NS HMI is required, connect via a serial con- nection, or via a CP1W-CIF41/CP1W-ETN61/ Ethernet adapter. Grid Connect Modbus/TCP Adapter Application and Setup Guide 2-13