Inside Machines: Crane Moves with IEEE 802.11n wireless
Collecting production, alarm, and maintenance data in production facilities is a critically important yet intricate task, especially in manufacturing plants with multiple moving parts, such as steel mills with overhead and gantry cranes. Such cranes can be the primary material handling system for the facility. Because of the range of motion of cranes (in some cases over a kilometer), using wireless Ethernet allows connectivity with moving equipment, without the safety hazards and risk of moving wires or fibers. In conjunction with the manufacturer’s IT department, Schneider Electric recently implemented wireless Ethernet at a steel mill, enabling the facility to collect vital data accurately, efficiently, and safely.
First, a high-speed IEEE 802.11n network was used to configure network access points to ensure wireless coverage for crane movements. Security of the wireless Ethernet was then established through MAC and IP address filtering, which is handled at the subnet mask level, and the crane network was isolated from the rest of the facility via subnet mask, MAC, and IP address. Each device assigned access to the crane network must have a separate MAC address listed for router/firewall access, and all wireless access requires SSID (service set identifier) and WEP (wired equivalent privacy) key security.
Each crane was then assigned its own Ethernet network and integrated with multiple Schneider Electric Magelis human-machine interface (HMI) and industrial PC (IPC) units, Modicon M340 programmable automation controllers, Advantys distributed I/O, Connexium Ethernet switches, and crane VFDs. Each of these devices featured built-in web servers with product-oriented configuration and maintenance web screens, as well as assigned IP addresses and web server password protection. To increase functionality, the crane-based Magelis IPC HMI units were programmed with Vijeo Designer HMI software, which enabled them to serve all HMI screens via a Web Gate remote access function. With product and HMI web server access, maintenance personnel were given access to all alarm, diagnostic, and parameter information for the control system, as well as programming access to the M340 PAC and Magelis HMIs.
Additionally, a Vijeo Citect SCADA (supervisory control and data acquisition) system was integrated into the plant control system, to monitor all cranes for key performance indicators (KPI), maintenance, and alarm data. And to reduce network communications and increase data protection, the crane-based control systems publish data to the SCADA system—eliminating the need for the SCADA to poll the cranes for data. In the case of a plant wireless system failure, the crane-based control system stores up to seven days’ worth of data. When the network connectivity is reestablished, the stored data will be automatically published to the SCADA system. The Vijeo Citect system also uses a web server to publish screens and report data, allowing multiple users to display the plant-level data without having to install a SCADA software package on every computer.
This wireless industrial networking system, after implementation, allowed the steel mill to capture manufacturing data in the most accurate and least hazardous way possible, enabling the facility to increase efficiency and overall production.