This case study was written by Mateus Henrique da Silva in Portuguese and posted on LinkedIn. Select the language version below.
Imagine the following situation: A laboratory has a test plant instrumented completely with Foundation Fieldbus technology and needs to quickly include a PLC in its topology for the validation of a new control strategy.
Usually a PLC does not have native connectivity to instruments in the Foundation Fieldbus network, requiring the use of a card to adapt the controller to the network. Purchasing this card only for validation of a new strategy may not be economically viable, in addition to delaying the project.
A decision had to be made to either give up on the new control strategy entirely, or postpone the completion of the final project. I decided neither situation was acceptable.
With the bridge feature between OPC servers, known as OPC Bridge, it is possible to exchange data between two OPC servers from different manufacturers, this allowed them to connect instruments of different technologies as long as they have OPC servers and clients. Using this technology, it is possible to access the variables measured by the instruments of the Fieldbus plant via the PLC.
This technology was applied in the didactic distillation plant of the laboratory of the Federal Fluminense Institute to validate the interoperability om the OPC Training Institute. OPC Expert is an intuitive and easy-to-use interface tool for diagnosing and solving OPC connectivity problems, it has its own OPC UA server and in addition to the OPC Bridging feature it also has many other features, including OPC Tunneling and Trending real-time and historical data.
By using the software as an intermediary between the Fieldbus instruments and the PLC, it was possible to connect the two OPC servers and then exchange data between them, enabling the implementation of new strategies previously not explored in the didactic plant.
“We obtained excellent results using OPC Expert to exchange data between two different OPC servers in different machines, the software allowed us to easily configure the bridges and configure the update rate of the variables,” da Silva said
“We came to the conclusion that using OPC Expert to do the bridges was the way to go, since the level control was properly controlled in a stable way and the delay time of data from one OPC Server to other by OPC Expert didn’t impacted on the control process,” he said.
Mateus Henrique da Silva and Vinícius de Paula Parente were engineering students at the Instituto Federal Fluminense in Campos dos Goytacazes, Brazil. For the final project of his degree, da Silva and Parente chose to utilize OPC Expert to expand the possibilities of control strategies in the didactic plant of the Insituto Federal Fluminense.
The didactic distillation tower of the Federal Fluminense Institute has instruments interconnected in an industrial Foundation Fieldbus network that can be configured from a computer in the lab. Despite its efficiency in providing practical experiments, the plant is limited in terms of control strategies.
da Silva and Parente wanted to improve and expand the number of control strategies by adding a PLC to the plant topology. They already had OPC servers from SMAR and Phoenix Contact. However, two OPC servers are unable to communicate with each other directly. So, they used OPC Expert as a bidirectional bridge to read data from one OPC server and write to the other. OPC Expert enabled da Silva and Parente to use their PLC as a controller, ensuring interoperability between instruments from different manufacturers.
Imagine a seguinte situação: Um laboratório possui uma planta de testes toda instrumentada com a tecnologia Foundation Fieldbus e precisa da noite pro dia incluir um CLP em sua topologia para a validação de uma nova estratégia de controle.
E agora, o que fazer? Devo desistir da minha nova estratégia de controle? Talvez adiar a entrega do meu projeto? Nada disso!
Com o recurso de ponte entre servidores OPC, conhecido como OPC Bridge, é possível trocar dados entre dois servidores OPC de fabricantes distintos, isso nos permite conectar instrumentos de diferentes tecnologias, desde que eles possuam servidores e clientes OPC. Utilizando essa tecnologia é possível por exemplo acessar pelo CLP as variáveis medidas pelos instrumentos da planta Fieldbus.
Essa tecnologia foi aplicada na planta didática de destilação do laboratório do Instituto Federal Fluminense para validar a interoperabilidade entre os dispositivos de diferentes fabricantes, o software utilizado para isso foi o OPC Expert, da OPC Training Institute. O OPC Expert é uma ferramenta de interface intuitiva e de fácil uso para diagnósticos e resolução de problemas de conectividade OPC, possui seu próprio servidor OPC UA e além do recurso de OPC Bridging conta também com os recursos de OPC Tunneling e Trending.
Ao utilizar o software como intermediário entre os instrumentos Fieldbus e o CLP, foi possível conectar os dois servidores OPC e então trocar dados entre eles, possibilitando a implementação de novas estratégias até então não exploradas na planta didática.E você, já conhecia esse recurso para trocar dados entre servidores OPC? Sinta-se a vontade para comentar ou entrar em contato para trocarmos informações.