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Panel Meters - Counters - Timers - Transmitters, 4-20 mA & Modbus - Ethernet - USB - RS485 - RS232

LNET485 Ethernet-to-RS485 Converter Board for Laurel Electronics 1/8 DIN Instruments

Ethernet-to-RS485 device server board

Key Features

  • Connects a host meter to an Ethernet LAN while also acting as a gatway for up to 31 Laurel devices on an RS485 bus.
  • Includes an RJ45 jack to the Ethernet plus an RJ11 jack to the RS485 bus.
  • Suitable for all 1/8 DIN Laureate DPMs, counters, timers & remote displays.
  • Complemented by Instrument Setup software which discovers Nodes and meters, by Node Manager software, and by built-in web server.
  • Selectable baud rates to 9600.
  • Isolated from meter and power grounds.
Description

The Laureate LNET485 Ethernet-to-RS485 Converter Board 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 set to half-duplex operation. That board provides dual RJ11 connectors wired in parallel for RS485 daisy-chaining using commercial 6-wire RJ11 data cables (Laurel P/N CBL03), with no need for a hub.

Laurel meters connected to a PC via an Ethernet-to-RS485 device server

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 Node 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.

Laurel meters connected to Internet via an Ethernet router

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.

Laurel meter connected to PC via Ethernet cableBuilt-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.

Specifications
LNET485 Ethernet Board
Baud rates 300, 600, 1200, 2400, 4800, 9600
Devices per Ethernet line 1 host meter for Node plus up to 31 meters on RS485 bus
Ethernet connector RJ45 jack
Ethernet cable 10/100 Base-T
Ethernet compliance IEEE 802.3
Devices per RS485 line Up to 31
RS485 connector RJ11 jack
RS485 compliance EIA/TIA-485
Isolation 250V rms working, 2.3 kV rms per 1 min test
ESD Protection 15 kV per IEC 1000-4-2
EMI Immunity 10 V/m per IEC 1000-4-3
EFT Protection 2 kV per IEC 1000-4-4
Short Circuit Protection Continuous
Protocol Modbus RTU (converted to Modbus TCP).
Modbus RTU / TCP
Standards Compliance Modbus over Serial Line Specification V1.0 (2002)
Conversion from RTU to TCP Automatic
Data Formats (selectable) 1. No parity, 8 data bits, 2 stop bits
2. Odd parity, 8 data bits, 1 stop bit
3. Even parity, 8 data bits, 1 stop bit
Protocol Type Master-slave, query-response command mode
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