Before yearend, the Detroit-based automaker plans to launch a pilot project in an Asia-Pacific plant that relies on a reduced-footprint control system with potential to significantly reduce installation, maintenance and IT overhead costs, says Jeff Sousley engineering group manager for plant floor systems development within GM’s Controls, Conveyors, Robotics and Welding group.
The system relies on Rockwell Automation ControlLogix programmable automation controllers (PACs), for which GM engineers have written scaled-down code based on GM’s common software specification, and a “Windows CE-based module” that resides in one of the ControlLogix controllers, Sousley says. If pilot testing pans out, GM hopes to deploy the system in low-cost countries where the use of traditional, full-scale automation and MES is cost-prohibitive for the company and its joint venture partners.
No big MES
The GM system is not designed for use in large, body shops using 500 PACs or programmable logic controllers, Sousley stresses. It is rather intended for applications employing perhaps 20 to 30 controllers. “We’re certainly not duplicating all the high-level functionality that you would find in a state-of-the-art MES,” says Sousley.
But the code developed for the plug-in CE modules does provide sufficient built-in functionality to handle network self-configuration tasks for the controllers, eliminating the need for upper-level configuration by an IT staffer during start-up and process changes, Sousley notes. In addition, the module provides diagnostics and troubleshooting information so that the system should be maintainable without IT support on the plant floor—ideally, even by skilled trades employees, Sousley says.
The system will also support basic report generation. And because the CE module includes a built-in Web server, the system will integrate data from multiple controllers across an EtherNet/IP network for viewing on any controller human-machine interface (HMI) or engineering laptops on the network, negating the need for additional PC-based viewing devices on the plant floor.
By eliminating plant-floor PC-based devices, the small footprint system will enable GM low-cost sites to avoid a lot of traditional PC “baggage,” Sousley points out. “It’s something that once you get it configured, you can let it run without a lot of the usual PC maintenance like operating system upgrades, security patches and things like that.”
Scale to need
As a result, though functionality will be reduced compared to a full-scale MES, “the cost to install and maintain this system should be much less than what we’ve traditionally done,” Sousley says. Conservatively, he ventures, the savings should be at least 50 percent.
“We always talk about scaling the system to the need, and this is an example of that,” Sousley observes. “It’s a move to making systems more scalable, while keeping certain elements common, such as the code base. The idea is that we can implement systems for low-automation applications, and then scale them up later as required.”
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