Heytex, a brand of the German-based Heytex Bramsche GmbH, is a global developer and manufacturer of high-quality technical textiles. Their portfolio includes sophisticated and unique products fabricated and engineered using complex textile technology, such as signage, banners, boats, sales, barriers, and other technical textile products for a variety of customers. Electronic Drives and Controls (EDC), a recognized leader in the design, upgrade, and service support of drive and PLC Systems, recently helped Heytex significantly improve industrial textile coatings equipment for a military customer and double their overall production capabilities.
Heytex had previously purchased a used paint line machine at auction that consists of two parallel production lines sharing the same painting booth and oven sections which could run concurrently or separately. However, one of the lines (Line 2) sat idle for approximately three years before Heytex sought help improving its operability to produce spray-painted industrial camouflage textiles for a military customer. Parts from Line 2 were scavenged to keep Line 1 running.
Originally, Heytex would receive an AutoCAD file from their military customer that specified the geometry of the desired pattern to be painted by the machine. Each line has six drives: 3 VFDs for web handling and 3 servo drives to traverse the paint heads. The process begins by feeding industrial fabric through a conveyor from an unpainted fabric roll. Next, three spray heads move across the fabric in a coordinated fashion applying green, brown and black paint resulting in a specified camouflage pattern. The machine then dries the fabric in a tunnel oven and rolls it into a finished painted textile roll.
As purchased, each section of the machine used a personal computer with an obsolete Windows XP operating system and a soft Allen Bradley Programmable Logic Controller (PLC) for the unwinding and painting of the fabric. Two physical Omron PLCs handled downstream control, one for the oven and conveying systems and another on the rewind section. A proprietary software run on the XP operating system utilized algorithms to control the paint from the spray heads and help to convert the customer’s CAD files into control commands, a very cumbersome process requiring much manual intervention.
Another problem impeding the retrofit plan was a tremendous lack of documentation and labeling. This coupled with obsolete controls, proprietary software and a burdensome workflow with no known support prompted Heytex to task EDC with improving the machine with an integrated hardware and software design.
EDC’s approach was to streamline the control architecture ensuring that the PLC, drives and HMI were from the same manufacturer and would all be on the same communications network. Three disparate control programs were consolidated into one PLC, eliminating the need for a machine-based computer, soft PLC and monitor. The Siemens S7-1500 PLC and S120 drive platforms coupled with a 12-inch Comfort Panel were an excellent fit for this application.
Siemens’ S120 Sinamics Smart line module and common DC-bussed drives provide energy saving load sharing across the six drives and is able to regen excess AC voltage back to the incoming power line. Line drives were previously controlled in a start/stop mode and could only run at other speeds by manually changing the internal drive parameters. The S120 system provided full speed control capabilities as commanded by the PLC over a ProfiNet network.
The S7-1500F failsafe PLC simplified safety component wiring, especially given that three new cable-operated switches (safety rope pulls) were installed at the Unwind Exit, Paint Booth Entry and Rewind, improving the overall safe operation of the line. All main control components communicated with the PLC over a single ProfiNet control network including six VFD and servo drives, two remote I/O hubs and a new 7” HMI located at the Rewind section.
In addition to the cable-operated switches, other mechanical upgrades included a specially designed tension control system for the Unwind, adapters to couple new servo motors to existing spray head linear actuators, a line speed encoder at the oven exit and a linear position transducer for accumulator feedback. The EDC Field Installation Team installed and wired the new elements on Line 2 and ensured their proper functionality.
As previously mentioned, EDC consolidated all PLC logic into one CPU that closely communicates with the new HMI and S120 drive system. A user-friendly HMI screen and a recipe system were incorporated to improve the operator’s experience running the line. An offline program to convert the customer’s CAD files to data the PLC could use for proper control of the spray heads was a crucial part of the upgrade. EDC’s Project Engineer wrote an open-source Java script/HTML interface that could be modified by anyone with those computer language skills, eliminating the proprietary nature of the previous software incarnation.
Another key element of EDC’s retrofit is their documentation. A full set of wiring schematics was created that included reference for all components, wire numbers and a terminal plan. The customer was given a physical binder with hard copies of the drawings and digital copies of the control programs, the CAD conversion program and component manuals. A Tosibox remote access module was installed and connected to the machine’s control network. When connected to the internet, this device provides an ultra-secure VPN tunnel for remote monitoring and troubleshooting.
The improvements EDC made on Line 2 were substantial. Heytex went from a non-operational line whose parts were being cannibalized to keep an adjacent line running to a fully functional, efficient line with a state-of-the-art control system. Improvements included:
- Streamlined workflow making it easier to go from the customer’s drawing to product runs, eliminating a full set-up step
- Open source programs that can be modified and improved by any qualified service provider, eliminating proprietary software
- An energy-efficient control architecture that is rugged, orderly and fully documented without reliance on ever-changing personal computer hardware
- Improved control of the Oven conveyor, Tensioner and Rewind motors including better accuracy and synchronization through all speed ranges
- Improved Accumulator control that prevents finished product from touching the floor as was the case during Rewind roll changeover
- User-friendly operator interface screens with more relevant operational feedback, alarms, messages and maintenance screens
- New capability to switch between patterns in the middle of a single roll and stop and resume a pattern if there is an Estop or alarm, potentially saving hundreds of yards of material per year
- Remote monitoring and troubleshooting capability which was utilized to its full potential one month after start-up when Heytex needed to recalibrate Line 2 for new material. EDC was able to support them remotely and avoid a costly service trip from New Jersey to Virginia.
- A retrofit platform with documentation, programs and drawings that can be utilized to upgrade Line 1, ensuring production viability for years to come
To sum up the benefits of the project, EDC’s VP of Engineering Chuck Dillard said, “If you look back, only Line 1 was operable. Now both lines are running, and Line 2 runs more efficiently with higher throughput than the machine’s original design.”