An Open Source Approach to Reusable Objects
Chicago-based DMC has new software objects in the Siemens Open Library to ease HMI, PID loops, drive control setup and more.
Portal libraries have become a popular technique for storing a number of different objects that can help developers get things done quickly using a common code base. Open source programs provide a way for engineers and programmers to help each other shorten development cycles.
DMC Inc., a Chicago-based Siemens Solution Partner, and Siemens have combined portal libraries and open source concepts to create the Siemens Open Library, which holds a number of blocks that can be used to speed industrial development. The modules are free to use and change under an open source license.
DMC created the library blocks, which augment the basic tools offered by Siemens. Most of these modules were developed to meet common needs as DMC worked with customers in diverse fields.
Before putting its open source blocks on line, the national company worked closely with Siemens to create documentation and provide additional testing to ensure that the modules would work in a range of applications. The two companies also worked together to streamline operations for those who want to leverage the benefits of others who work in similar fields.
For example, there’s plenty of reusable code, so users won’t have to do a lot of copying and pasting, or to do repetitive tasks. Users are also free to alter or augment items from the Siemens Open Library to meet their more specialized requirements. If they decide that these enhanced blocks might be useful to others in their specific field, they can redistribute or even sell them without doing anything more than telling others that open source technology is included in the module.
The library’s offerings can provide major benefits. In a webinar entitled “Developing PLC and HMI Code Faster Through Use of the Siemens Open Library,” John Sullivan of DMC told how a single engineer was able to set up manual controls so a butter-pumping customer could respond to an emergency situation. Library modules made it simple to get the facility back in action with minimal negative impact.
There are plenty of blocks to start with. The library currently holds a range of objects including function blocks, user-defined types, pop-up faceplates and icon faceplates.
Digging deeper, the library holds a pair of UDTs. One integrates with the human machine interface to provide large amounts of data to the HMI. Another provides all the errors for those blocks.
A Pop-up Faceplate is tied to the UDT for manual control. It handles a range of tasks such as settings for alarm messages, set point settings and various controls. Another Faceplate, called an Icon Faceplate, shows the basic amount of information that can be clicked to provide a full pop-up.
All the modules in the Siemens Open Library are well documented by DMC and its partner, Siemens. This documentation is extensive, beginning with a library overview for the blocks. The documentation also includes best practices for implementing each of the blocks, along with some of the best ways to set up these components.
The set up information is meticulous, going through every step that must occur as that object is configured. The detailed block overview is equally comprehensive. It includes information on every input and every output along with every UDT used by that block, with information on how each block functions.
The support data also helps users employ the HMI alarm generation tool, explaining how to generate alarms and alarm texts using Microsoft Excel macros that are included in the tools. The Excel macro is used for generating alarms for the Library Objects, or custom alarms, for example, when data blocks include Boolean data.
The PID Function Block gets special attention since it interfaces with the PID_Compact technology object built into Totally Integrated Automation Portal (TIA Portal) engineering platform.
Documentation for custom library objects tells users how to make changes, providing examples that show how modules can be set up.
A number of specific blocks are available. One for G Series VFD controllers works with any VFD controller and G series drives. It makes it simple to control the hardware in automatic or manual modes. An analog VFD block permits controlling of analog VFDs from the PLC. A two-state solenoid valve block and an analog solenoid valve block are also available on the site.
All the Siemens Open Library modules can be deployed on many Siemens platforms inside TIA Portal: the S7-1500, S7-1200, S7-300, S7-400, WinCC Comfort and WinCC Advanced. Going forward, WinCC, WinCC OA, and SiMotion will be included in the list. As more platforms are added, the number of programs will also increase.
Some of those will come from DMC and Siemens, which have added several blocks in a supplementary section that’s clearly marked to show that documentation and testing have not yet been completed to the same rigors of the main library.
There’s hope that many more modules will also be added by users and integrators who want to share. The website makes it straightforward for people to share bug fixes and post something they’ve developed on the site. At present, DMC is the site custodian, but the company hopes that the community will eventually move to an open source platform where it’s managed by volunteers.Have an Inquiry for Siemens about this article? Click Here >>