We recently had a need to connect to a PowerLogic BCM42 through a Barionet-50 from Barix. While the Barionet-50 speaks Modbus/TCP for itself, it does not perform as a TCP/RTU gateway for devices hooked up to it via the RS485 port which is a straight serial gateway. Our project is being implemented in ruby so we started with the excellent RModbus gem and modified it to send Modbus/RTU commands via TCP and it works perfectly. This solution is also significantly cheaper than buying an off-the-shelf Modbus TCP/RTU gateway as those tend to *start* at about $400 and rapidly get more expensive.
require 'rubygems'
require 'rmodbus'
ModBus::RTUViaTCPClient.connect('10.10.100.33', '10002', 4) do |cl|
total_ma = cl.read_holding_registers(0, 42).inject(0) { |acc, i| acc += i; acc}
puts "Total mA: #{total_ma}"
end
$ ./test.rb Total mA: 12510
Our code for accessing Modbus/RTU devices via TCP can be found at http://github.com/kreynolds/RModBus
