Connecting PLCs to an Enterprise Database

Michigan-based TranTek Automation designs and builds automated welding, material handling, inspection, and assembly systems. The company is known for its preconfigured robotic welding cells, as well as robot transfer units, tip dressers for resistance welding, conveyors, and retractable locating pins.

One automation project the company recently secured required TranTek to develop a system consisting of six plasma cutting robots that could synchronously apply plasma torches to large, made-to-order steel structural parts using various production recipes. Plasma cutters cut metal by sending air or an inert gas through a plasma torch to spark an electrical arc. This forces the plasma through the torch tip to cut metal. The arc of a plasma cutter can reach temperatures of 45,000° F.

tManager downloads recipes and manufacturing instructions directly into the controller.

While this application was straightforward enough for TranTek, one challenge for the company was figuring out how to connect the machine controller to the customer’s IT system. This step was necessary because “all of the production data for the steel parts are stored in a large database within the customer’s central server,” said Jeff Ebert, senior controls engineer at TranTek Automation. “Creating an upward-level connection between the PLC (programmable logic controller) and server created a lot of challenges for us. We would have spent weeks just writing the code so the system could access and download the recipe files to the PLC.” This type of connection between controllers and enterprise-level databases has long been possible, but typically requires the development of custom code to connect the two systems. To avoid writing custom code for a one-off application, TranTek decided to use the tManager Enterprise Appliance Transaction Module from Softing. This device is designed to “seamlessly connect” enterprise-level databases with PLCs, according to Softing. With tManager in place, TranTek Automation was able to deliver a plasma cutting robotic system that could communicate with its customer’s enterprise database without having to write any extra code. More importantly tManager addressed the reason why TranTek’s customer wanted to connect the system’s PLCs to their enterprise database—to download recipes and manufacturing instructions directly into the controller.

tManager enables bi-directional data exchange between enterprise systems and PLCs.

For this application of tManager at TranTek, ControlLogix and CompactLogix control platforms from Rockwell Automation were connected to the customer’s enterprise databases for downloading of recipe files. In addition to downloading daily recipes from the database to the ControlLogix platform, tManager is also used to upload production metrics from the ControlLogix platform back to the database to inform the enterprise system when production runs are complete.

tManager can be used with a variety of enterprise databases, such as Microsoft SQL Server, Oracle Database, MySQL, AWS IoT SiteWise, and Azure Cloud. In addition, via the module’s front Ethernet port, drivers can connect tManager to PLCs from Allen-Bradley, Siemens, and Schneider Electric.

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Ebert added that configuration of tManager is simplified because, once it’s installed into the ControlLogix rack, the transaction module automatically enumerates PLC and database tags and structures and can monitor tags without touching the PLC logic. “We also avoided the code maintenance headaches associated with custom software,” he said.

“Thanks to the bi-directional data exchange capability of tManager, our customer can now confirm and update shipping orders directly within the ERP system, enabling them to fulfill their orders for steel parts faster and speeding their time to market,” said Ebert.

An in-chassis module, tManager minimizes engineering and installation time.

An added benefit of using the enterprise database to store complex production data instead of the PLC frees up “a ton of valuable resources in your PLC, such as memory, storage, and performance,” said Deane Horne, director of marketing at Softing. “You can also de-couple manufacturing line changes from PLC logic changes. For example, it's much easier and safer to update an SQL table than to edit PLC logic.”

“tManager enabled us to design a system that could seamlessly bring in the production data for thousands of steel parts—everything from how the steel has to be cut to where holes should be located along the axis,” Ebert said. After tManager downloads the manufacturing recipes from the database to the PLC, the plasma cutting robots can automatically adjust variables, such as amperage and gas flow.

Ebert also noted that the TranTek customer is so pleased with this system that they’ve “decided to move forward on a long-term plan to automate and upgrade their systems, and tManager has become a standard for all their installations.”