For engineering and system integration firm Trident Automation, creating and keeping customer trust is as important as understanding the technology being implemented. To that end, the team does everything it can to limit downtime during a control system migration for its customers in the continuous process industries. When the technology deployment involves moving from a legacy DCS to a modern control architecture—which happens a lot these days as manufacturers digitalize operations—there are even more risks associated with data and knowledge transfer.
For these reasons, Trident began looking for ways to quickly validate code, reduce commissioning time, mitigate risk when implementing logic changes and lessen the learning curve for operators. The team found a solution in Siemens’ simulation software SIMIT, which replicates real-world I/O conditions and provides comprehensive testing and validation of application code. The software gives engineers a way to test code and virtually commission projects in a way that protects real-time operations. It can also prepare operators to run the new system via virtual training.
SIMIT can handle different types of simulation, including simulation of signals coming from and going to the automation system, simulation of drives and sensors, and simulation of plant behavior. It can also emulate controllers through the use of Virtual Controllers or be coupled to real controllers.
西门子组件库,FLOWNET CHEM-BASIC, are extensions of SIMIT providing component types that simulate pipeline networks and equipment commonly found in chemical and pharmaceutical industries, respectively. Interconnecting the library components enables a model of a flow network to be generated in SIMIT. Flow networks for water, steam, liquids or ideal gases can be created. Using CHEM-BASIC, mixtures of substances are modeled as pseudo-single substances with corresponding mixture properties.
Beyond the simulation of I/O points, another benefit of SIMIT is the clear separation between simulation and production. “There is no simulation code at all in the automation project,” said Jeff Meneau, a controls designer for Trident Automation who was presenting at Siemens Automation Summit 2018 in Florida. “We used to put the function blocks in simulation [mode] and add simulation code to test and then we’d get to the site for startup commissioning and wonder why some function blocks weren’t working. Well, it was because simulation [mode] was not removed from every function block. But we don’t have to worry anymore because the simulation code in SIMIT is completely separate. There is no errant code sitting in the controller and using controller resources, so people won’t get confused when trying to follow code around because the simulation is in a different spot.”
In addition, SIMIT software provides early detection and correction of errors in code during virtual commissioning, providing a way to do control loop checks and sequences as well as simulate the entire plant operation during factory acceptance testing (FAT). According to Meneau, customers typically come to the Trident office for initial training, and the simulation provides the capability for them to actually see the system run sequences, allowing them to be more engaged early on in the FAT process. Once the system is being set up on site, “we’ve reduced the commissioning time, which builds customer confidence,” Meneau said.
Trident can also use SIMIT to manipulate time by speeding up or slowing down a process to check settings. For example, one of Trident’s clients had a fermentation sequence that required additional settings. In the real world, a fermenter takes eight hours to fill, so Meneau accelerated the time to fast fill it in SIMIT. “So I don’t have to sit and wait for that fermenter to fill,” he said. “I can also slow it down to watch the logic work.”
Future time savings is important, too, as all of the simulation logic is archived so that it does not have to be recreated in the event of troubleshooting a problem. “I once got a call from a plant manager saying that a dryer was tripping every time a certain conveyor shut down. I couldn’t see anything that would cause that, but a light bulb went on that I had it all simulated. I got their latest archive, ran through the scenario, shut the conveyor off and nothing happened, so it validated what I was seeing in the code. I had him log in to my PC in the office to see that the logic was not causing the dryer to trip and they later found out it was a field wiring issue,” Meneau recalled, noting that the hardest part of having a new DCS is determining whether problems are a startup issue or a DCS issue. “We can test the logic before it gets to the site so that everyone is more comfortable with it.”
SIMIT can also be used to train operators who need to get used to a new HMI. Trident starts the project by providing a demo app that allows operators to get familiar with what alarming looks like, how to open and close valves, for example, giving them the ability to play with the system before it goes live.
“We want to engage operators more and have them sign off that they can turn off a valve, for example, because it only makes their lives easier,” Meneau said. Overall, SIMIT allows Trident to reduce onsite DCS commissioning time by 10-15 percent and it gets everyone involved, which has helped the integrator meet its initial goal. “We build customer confidence.”
