Ethernet-to-RS485 Gateway Board P/N LNET485 for Laurel Electronics 1/8 DIN Instruments

The Laureate Ethernet-to-RS485 Gateway Board P/N LNET485 plugs into a host 1/8 DIN digital panel meter, counter or timer to provide a 10/100 Base-T Ethernet interface via an industry-standard RJ45 jack for that meter. It also provides an RJ11 jack for interface to an RS485 bus, which can support up to 31 Laurel meters equipped with Laurel's RS485 interface board jumpered for half-duplex operation. That board provides dual RJ11 connectors wired in parallel for RS485 daisy-chaining using commercial 6-wire RJ11 data cables (Laurel cable CBL03), with no need for a hub.

Instrument Setup software is a free Windows-based application which automaticaly discovers all Laureate Ethernet Nodes on the same Local Area Network (LAN) as the PC, plus any Laureate devices (or meters) associated with that Node. The devices can be the Laureate host meter for the gateway board and any remote Laureate meters on the RS485 bus. Instrument Setup software can be used to program any Laureate instrument, for example to scale the meter reading, scale the analog output, and set relay setpoints. For programming, the PC running Instrument Setup software can be connected to the LNET485 host meter via the LAN or directly to the PC via an Ethernet cable. It can also be connected to each remote RS485 meter via Laurel's cable CBL06. Meters and counters can also be programmed directly from their front panel.

Node Manager software is a free Windows based application which also automaticaly discovers all Laurel Ethernet Nodes on the same Local Area Network (LAN) as the PC. It adds capabilities such as naming the Node and associated devices, entering email addresses for alarm notification and data requests, selecting the Node's time zone for time-stamping of streaming data, and setting communication parameters for associated meters. It allows emails or text messages to be sent in response to requests from the host computer, periodically, or when devices encounter an alarm condition or go off-line. Node Manager is described in our Ethernet Manual.

On a Wide Area Network (WAN), such as the Internet, the host computer running Instrument Setup software or Node Manager software is outside of the LAN and cannot discover the Nodes on the LAN. The public IP address of the LAN's router must then be entered manually. Web server software built-into each Node can also be used to discover and configure Laurel Nodes over the Internet.

Built-in DHCP server capability allows Laurel Nodes to constitute themselves into a network and be connected directly to a host computer when no router or dedicated DHCP server is present, as illustrated above. When a Node fails to find a DHCP server that responds to its request for a private IP address, it assigns one. When several Nodes fail to receive a Private IP address, they mutually agree to make one of the Nodes a temporary DHCP server that assigns a Private IP address to each device on the network.

The Modbus TCP protocol is fully supported. Modbus command cannot only be used to read meters remotely, but also to change setup parameters like setipoints. Conversion to form Modbus RTU to Modbus TCP is transparent so that an Ethernet application can use the Modbus RTU protocol.

Laurel's LNET Ethernet board can be used as an alternative to the server board for networking multiple meters. Each meter will then need to be connected to the network via an Ethernet router, switch or hub, and its own Ethernet cable.