This video describes the Default gateway address, and how it can be used to communicate between separate subnets.
What do we do when the IP address and the subnet mask of our Ethernet devices will not allow them to talk to one another? This is where the Default gateway comes in. A default gateway is a device (router, Server, Pc, etc) that will route communications between networks that are not on the same subnet. Don’t worry It is a lot simpler that it sounds. Here let’s see an example. We have these two PLC’s and based upon their IP address and Subnet Mask they can to talk to one another directly, but now we need to program them from a Pc that is not on this subnet. The most common way to resolve this would be to add a router into the network. This router will have an IP address assigned for each port that the separate subnets are connected to, and that IP address will have to be placed into the Default gateway address setting for each device. Once this is done, the communication from the PC will then be passed through the router over to the PLCs subnet. Don’t get too hung up about this being specifically PLCs or PCs. This can be done for any type of Ethernet devices that allows for a default gateway setting. Be it PLCs, HMIs, PACs, or Field I/O If you need any help with using an Automation Direct’s Ethernet capable device please contact AutomationDirect’s free, award winning Technical support team during regular business hours – they will be happy to help. And don’t forget the forums. There are lots of folks there that love to share their years of experience. Just don’t post questions for AutomationDirect’s Technical support staff there, they do not monitor the forums on a regular basis.