The RS-485 network is a central part of many industrial control and home automation installations. The RS-485 specification requires that each module be connected by a daisy chain of cable with terminators on each end. However, most people wish to wire at least part of their RS-485 networks in a star or home-run configuration because it is easier to wire, troubleshoot, and manage. Stars (and stars on stars) often result in RS-485 network problems due to improper termination and signal reflections. These problems can result in severe network instability, or worse, networks operating on the edge that are subject to failure, often at the worst times. To properly use a star configuration with an RS-485 network, each leg of the star must be its own isolated RS-485 network. This is where an active RS-485 hub comes in.
The RS-485 active hub provides 8 isolated, actively driven RS-485 ports for connection to remote nodes. Each port creates its own independent RS-485 network. The hub comes with a 12VDC 1Amp power supply which can be used to power devices on each port. If you already have plenty of 12VDC power, the hub can be powered via the external terminal block instead of the included power supply. Up to 32 devices can be connected to each port (128 if your devices use 1/4 power interface ICs). The hub uses ESD hardened RS-485 ICs and transorbs on each port for surge suppression. Each port has an indicator for incoming traffic activity and a jumper allowing the leg to be removed from the network for troubleshooting. Multiple hubs can be used to properly implement multiple stars. This hub is a must for any automation installation that doesn’t use a daisy chain to connect its RS-485 nodes.
