Discrete processes : OPC Servers to database: historians or SQL database?

[Christ0phe 0]

Hello Historians and databases specialists, We are looking for solutions to upgrade our current Labview-based application that takes data from PLCs through OPC servers and store them into a home-designed binary file structures, locally on a PC. These are our specifications: - All our processes are parts driven (discrete). We are not dealing with time-based processes - One part is produced every 1min - The data acquisition is triggered by the polling of a 'trigger' (counter) and when this counter increments the application get all related data. In other words, nothing happen during 1min (just the trigger scrutiny) and all data transfer is once per minute. - Per cycle we are taking about 15.000 tags (16 bits words) per machine - Per plant we have roughly 10 machines, all with a cycle time of 1 min. One PC today is connected to 1 or 2 machines. So 5 PCs per plant roughly. - Emphasis given on the visualization of the data close to the machine to help the operator in his process adjustments. Here the operator needs to visualize all parameters for a specific machine cycle, overlay profiles (a profile is a serie of tags for a defined cycle), graph parameters against cycles or against time (but even against time the different points of the graph mean a specific part produced) - We do not really have time constraints as to the time it takes to fetch and write the data into the database. It can take 10s, we do not really care. - Open database so that people can make cross-machines analysis of data (data mining) - Cost-effective solution An internal discussion lead to considering that instead of writing into a local home-made Database we could simply write into a centrally located SQL database (located on a plant’s server). I know that Historians could also be a way to go but do not understand the advantages that we would have especially considering the specs given here-above. What solutions would you recommend to implement or to study? Thank you very much to share some thoughts with me Christophe

[Ken Roach 194]

Hi Christophe, For my money, the best SQL-oriented HMI and data logging system on the market is Inductive Automation's Ignition software. I recently replaced a LabView application with some new logic controllers and Ignition software. The authors of the LabView system were skeptical, but once they saw the SQL tables being populated, almost effortlessly, with their data they were converts. Ignition works with most SQL Server software, and is Java-based so it's cross-platform. Their web-launched visualization is particularly easy to distribute among computers, since it requires only the installation of Java. One of the few drawbacks of Ignition is that their native OPC-UA communication server is limited to only a few PLC models. But you can use any existing OPC server with their OPC DA->UA bridge module.

[Christ0phe 0]

Ken, Thanks for your feedback. My question was also to see in what sense the implementation of an Historian could be of any help to us vs an SQL-only solution: This is what the current application provides to visualize the data: Visualization windows: the Labview application that we wrote provides several ways to visualize the data: For the local user close to the machine under supervision, operators mainly use the 3 following windows of the application: Window1/ All process data values for a machine (can be thousands of parameters) displayed for a specific cycle number selected. Displayed in a kind of two-columns table. The selection is either a cycle number or date/time (in this case the application fetches the cycle closest to the date/time requested) Window 2/ Some parameters are what we call profiles ie. collection of consecutive tags. Those must be displayed as curves for a selected cycle. For example after each cycle we collect pressure profiles, each profile being 500 consecutive tags. Window 3/ 5-graphs, each one able to display a parameter against cycle number or time. Even when time is selected as X-axis, each point will represent the value of the parameter for a part produced. The application also gives the possibility to set limits on parameters (different limits for different products). Those limits are displayed in the graphs of Window 2 and in the Window 3 interface as well. For more advanced users performing off-line analysis they use the same windows and also an interface that allows extraction of parameters into CSV files for further data mining. Thanks again for your thoughts.

[Eternity Sales 0]

Christophe, If you are looking for an OPC server product, you may want to consider KepserverEX from Kepware. It offers hundreds of communications protocols as well as plug-in options for further enhancements to your application, thus addressing many different requirements. More information can be found through the following links: Kepware KepserverEX Data Logger Plug-in Downloads There is additional information on the Eternity Sales website that can further assist you with Kepware's products, including software downloads, manuals and data sheets. Feel free to contact me via email if you have additional questions regarding Kepware's OPC server products Disclosure - Eternity Sales is an authorized Kepware Distributor. Stephen Luft info@eternity-sales.com Eternity Sales Website

[Christ0phe 0]

Hello Stephen, Thanks for your answer. Nevertheless I think you read my posts too quickly. Kepware OPC Server is already what we use to connect to our equipments. The questions raised are more : from OPC Server to database + visualization of the data, limits,... Thanks Christophe