By Roger Potter, Controls Engineering Manager, TGW-Ermanco
When you look at the history of distribution centers, the technologies associated with operating and maintaining these facilities have significantly evolved over the past 30 years. From the material handling perspective, relay logic and reams of paper schematics are technologies of the past. These have been replaced with supervisory control and data acquisition (SCADA) solutions that typically include the application of programmable logic controllers (PLCs), visualization systems, electronic documentation, Web interfaces and remote diagnostics.
With the advancements of these integrated and more complex solutions comes the introduction of new skill set requirements in order to maintain them. In a typical automated distribution environment, there may only be a few operations personnel at the facility responsible for overseeing what could be literally miles of conveyor or hundreds of thousands of automated storage locations. These new automated systems are not just mechanical anymore, but are integrated with sophisticated controls working to orchestrate systems where the customers' product is now delivered to workers at ergonomic goods-to-person picking and order fulfillment stations.
These operations people monitor the day-to-day operation of the system, but don't often have the high-level diagnostics skill sets required to troubleshoot and maintain these systems. This typically falls on the shoulders of their maintenance personnel.
For controls engineers designing these systems, this means we need to engineer and supply systems that are user-friendly while very integrated and complex.
At TGW, we design and build integrated logistics solutions for the material-handling industry. With the onset of technological advancements, the natural complexity of these systems dictates the necessity for a high-level SCADA solution with user-friendly operator and maintenance interface tools to monitor system statuses and provide definitive diagnostic capabilities for the multiple technologies of a material handling facility. Depending on the facility configuration and customer requirements, particular technologies included in a SCADA solution could include integration of a warehouse management system (WMS), warehouse control system (WCS), automated storage and retrieval system (ASRS), carton and tote conveyor, sortation and induction, lighting control, HVAC interface, Web camera and remote diagnostics.
A key aspect of designing these automation products from the engineering perspective is our use of advanced tool sets, such as auto code generators, hardware configurators and automatic tag definition that can be exported to a database and used for tag-based programming. We use the auto code generator to create standardized code blocks from a library of tested, proven and repeatable code.
Using technology to automate these material handling systems requires a balance between costs and features. Bells and whistles, including advanced self-monitoring, equipment effectiveness, and maintenance monitoring, increase the cost. Leave out functionality and the systems require too much human intervention. One positive aspect of this issue is, as more companies adopt the technologies used to make these systems user- and maintenance-friendly, they become more scalable and affordable, which opens the door for more companies to take advantage of the technology in their systems.
One example of how these systems are becoming more advanced involves remote diagnostics over a VPN high-speed connection to the SCADA system. This can be from within the distribution facility from an operations control room or from thousands of miles away by qualified technical support analysts. Being able to remotely troubleshoot a system and assist the customer without having a support technician on-site is one method of reducing the overall support cost to a customer.
For end-user companies that have internal IT departments, some prefer to not have external VPN access to their systems. In those cases, the SCADA system still gives them the necessary tools for diagnostics.
The holy grail of designing automated material handling systems is to create a system that can, in essence, manage itself, or at least manage by exception. This means the system automatically collects real-time data, and, if things are operating as they should, you don't meddle. If something happens, you can dive in and see what the issue is and more quickly solve the problem.
Connecting the mechanical and the control side of material handling automation systems is taking the WMS and WCS to new levels. Having conveyor that just keeps rolling 24/7 is no longer the way to go. Connecting the mechanical pieces of equipment to advanced engineered controls creates systems that are more efficient and cost-effective to operate, adding value and reducing costs for the companies that use them.