http://control.com/thread/1231757524

http://www.automation.com/automation-news/article/profibus-and-modbus-a-comparison

http://www.bapihvac.com/CatalogPDFs/I_App_Notes/Understanding_Current_Loops.pdf

http://www.sabereletronica.com.br/artigos-2/2426-cinco-dicas-para-reduo-de-rudo-nas-medies?start=1

http://www.control.com/thread/1274413114

http://wingpath.co.uk/evaluate.php?product=modmultisim

http://wingpath.co.uk/docs/modmultisim/simulations.html

http://wingpath.co.uk/modbus/modmultisim.php

http://pt.wikipedia.org/wiki/Profibus

http://www.modbus.org/docs/Modbus_over_serial_line_V1.pdf

http://www.samson.de/pdf_en/l452en.pdf

http://www.hw-server.com/obrazek/compare.gif

http://cds.linear.com/docs/en/product-selector-card/2PB_RS485fd.pdf