FINS/UDP

The FINS/UDP protocol is an Omron protocol which can be used by a PLC program to transfer data and perform other services with a remote PLC connected on an Ethernet Network. The FINS protocol allows Omron PLCs to communicate with the RMC75E, RMC150E, and RMC200. The RMCs support FINS/UDP.

The FINS/UDP protocol is an open application protocol developed and used by Omron Electronics Inc. This protocol is available over a number of media, including Ethernet and serial. Additional information is available in the CS1 Communications Reference Manual, available on Omron's web site: https://www.omron.com/oei.

The FINS protocol uses a three-stage addressing system: network address, node number, and unit number. These three address elements have the following purposes:

Network Address
This value identifies the network on which the target node resides. The PLC looks up this number in its Local and Remote Network Tables to determine which local unit number should be used to send out the request. For Ethernet systems, typically only the Local Network Table is used to map a network address (for example, 1) to the unit number on the ETN01 Ethernet Unit (for example, 0). See your Omron PLC and/or CX-Programmer documentation for details on setting up the Local and Remote Network Tables.
Node Number
This value identifies the node on the network given by the network address. For Ethernet networks, this number must be converted to an IP address. This conversion is done by the ETN01 Ethernet Unit. Three methods are available. In the Automatic Address Generation method, the IP address is derived by combining the ETN01's IP Network Address (e.g. 192.168.0.0) with the Node Number (e.g. 5) to get an IP Address (e.g. 192.168.0.5). In the IP Address Table method, each Node Number maps to an IP Address via an entry in an IP Address Table. In the Combined method, the IP Address Table is used first, but if the Node Number is not found in the table, then the Automatic Address Generation method is used. See the Omron ETN01 Ethernet Unit manual for details on these methods.
Unit Number
This value identifies the unit number on the rack of the remote node identified by the Network Address and Node Number.

The RMC does not require manually setting these values in the RMC. Only the IP address needs to be set in the RMC; see the RMC Ethernet Setup topic for details.

Addressing:

See the FINS Addressing topic for information on the FINS address of RMC registers.