1766-RM001A-EN-P MicroLogix 1400 Programmable Controllers ...

Communications Instructions 439Remote MessagesThe controller is also capable of remote or off-link messaging. Remotemessaging is the ability to exchange information with a device that is notconnected to the local network. This type of connection requires a deviceon the local network to act as a bridge or gateway to the other network.Remote NetworksDH-485 and DH+ NetworksThe illustration below shows two networks, a DH-485 and a DH+network. The SLC 5/04 processor at DH-485 node 17 is configured forpassthru operation. Devices that are capable of remote messaging and areconnected on either network can initiate read or write data exchangeswith devices on the other network, based on each device's capabilities. Inthis example, node 12 on DH-485 is a MicroLogix 1400. The MicroLogix1400 can respond to remote message requests from nodes 40 or 51 on theDH+ network and it can initiate a message to any node on the DH+network.TIPThe MicroLogix 1000 can respond to remote message requests, but itcannot initiate them.TIPThe MicroLogix 1400 capabilities are the same as the MicroLogix 1200 orMicroLogix 1500 in this example.This functionality is also available on Ethernet by replacing the SLC 5/04at DH-485 node 17 with an SLC 5/05 processor.Publication 1766-RM001A-EN-P - October 2008