Description
LAUREL
ELECTRONICS, INC.
Ethernet-to-RS485 Converter Board for
Laurel Electronics 1/8 DIN Instruments
Features
•
Connects a host meter to an Ethernet LAN while also acting as a server for up to 31
Laurel devices on an RS485 network.
•
Includes an RJ45 jack for connection to the Ethernet and an RJ11 jack for connection
to the RS485 bus.
•
Suitable for all 1/8 DIN Laureate DPMs, counters, timers & remote displays.
•
Complemented by free PC-resident Node Manager software and Node-resident web
server software, both of which can discover Nodes and meters.
•
Selectable baud rates to 19,200.
•
Isolated from meter and power grounds.
Meters on an RS485 bus connected to the Internet via an Ethernet-to-RS485 device server board.
The Laureate Ethernet-to-RS485 Converter Board plugs into
a host 1/8 DIN digital panel meter, counter or timer to provide a
10/100Base-T Ethernet interface via an industry-standard RJ45
jack. It also provides an RJ11 jack for interface to an RS485 bus,
which can support up to 30 additional Laurel meters equipped
with Laurel's RS485 interface board. That board features dual
RJ11 connectors for RS485 daisy-chaining using commercial 6wire RJ11 data cables with no need for a hub.
Discovery and setup of multiple Nodes on a LAN and multiple
meters on an RS485 bus is easily achieved via PC-resident Node
Manager software or Node-resident web server software.
Both methods automatically discover all Nodes on a LAN or
WAN, plus any devices connected to each Server Node via an
RS485 bus. They are used to configure each Node, such as
setting communication parameters, naming the Node and associated devices, entering email addresses for alarm notification
and data requests, selecting the Node's time zone for timestamping of emails and streaming data, and upgrading firmware.
Once configuration data has been stored in flash memory of all
Nodes, the PC can be disconnected. Details are in our Ethernet
Manual.
Data can be sent by Laurel Nodes in the form of real-time
stream data upon request or in the form of emails. Emails can
be sent in response to email requests from the host computer,
periodically, or when devices encounter an alarm condition or
go off-line.
On a Wide Area Network (WAN), such as the Internet, the host
computer is outside of the LAN and therefore must know the
public IP address of the LAN router to discover the Laurel Nodes.
Built-in DHCP server capability allows Laurel Nodes to constitute themselves into a network and to be connected directly
to a host computer when no router or dedicated DHCP server is
present, as illustrated below. 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.
Easy connection of an RS485 bus with Laureate meters to a PC via an Ethernet cable.
LAUREL
ELECTRONICS INC., 3183-G Airway Ave., Costa Mesa, CA 92626, USA • Tel 714-434-6131 • www.laurels.com 1
No need for a separate router or dedicated DHCP server.
The Modbus TCP protocol is fully supported. Conversion to
Modbus TCP is provided transparently by Laurel Nodes so
that an Ethernet application program can use the Modbus TCP
protocol while the meters use the Modbus RTU or Modbus ASCII
protocol. The Laurel ASCII protocol, which supports up to 31
digital addresses, can also be used if the only devices on the
data line are Laureate meters.
Instruments from other manufacturers can be operated on
the RS485 bus under control of our LTNET485 Ethernet-to-Serial
Device Server if the host computer supplies commands and
accepts responses suitable for these instruments.
Electrical Specifications
Ethernet Board Specifications
The Ethernet-to-RS485 Converter Board can be ordered as
an option for Laurel digital panel meters, counters and timers.
It cannot be ordered as a stand-alone product.
Laurel's separate Ethernet board can be used as an alternative
to the server board for connecting meters to a network. Each
meter will then need to be connected to the network via an
Ethernet router, switch or hub, and its own Ethernet cable.
Data rates
Devices per Ethernet line
Ethernet connector
Ethernet cable
Ethernet compliance
Devices per RS485 line
RS485 connector
RS485 compliance
Isolation
ESD Protection
EMI Immunity
EFT Protection
Short Circuit Protection
300, 600, 1200, 2400, 4800, 9600, 19200 bps
1 Node plus up to 31 on RS485 bus
RJ45 jack
10/100Base-T
IEEE 802.3
Up to 31 including the host meter
RJ11 jack
EIA/TIA-485
250V rms working, 2.3 kV rms per 1 min test
15 kV per IEC 1000-4-2
10 V/m per IEC 1000-4-3
2 kV per IEC 1000-4-4
Continuous
Protocol Specifications (implemented on the meter main board)
Modbus RTU
Standards Compliance
Data Formats (selectable)
Applicable Interface Boards
Conversion to Modbus TCP
Modbus ASCII
Standards Compliance
Data Formats (selectable)
Applicable Interface Boards
Conversion to Modbus TCP Main
Modbus over Serial Line Specification V1.0 (2002)
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
Ethernet, USB, RS232, RS485, RS485 Modbus
Automatic
Modbus over Serial Line Specification V1.0 (2002)
1. No parity, 7 data bits, 2 stop bits
2. Odd parity, 7 data bits, 1 stop bit
3. Even parity, 7 data bits, 1 stop bit
Ethernet, USB, RS232, RS485, Modbus RS485
Automatic
Laurel ASCII
Data Format
Protocol
Applicable Interface Boards
LAUREL
No parity, 8 data bits, 1 stop bit
Laurel Laurel ASCII
Ethernet, USB, RS232, RS485, RS485 Modbus
ELECTRONICS INC., 3183-G Airway Ave., Costa Mesa, CA 92626, USA • Tel 714-434-6131 • www.laurels.com 2
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