Ethernet field network enables new efficiencies for Honda.

Honda Motor Co., Ltd. has increased production and operation management efficiency at its 250,000 vehicle p.a. Yorii Plant in Japan by introducing a plant wide Ethernet-based CC-Link IE Field Network.

The Yorii plant operates as a centre for advanced vehicle production, introducing everything Honda has developed in the way of high-level production technology and high-efficiency production systems. The Yorii Plant also plays the important role as “mother factory” by introducing and sharing its production technology and know-how to plants worldwide.

For Honda the three key drivers in selecting an automation partner for the new plant were:

1. Build a simple and robust network worthy of the “mother factory”

2. Enhanced visualization of FA control devices, and streamlined operation and maintenance management

3. Flexible expansion and change as the network also supports communication of safety information

The first issue addressed was how to handle the overall network architecture for the vehicle body assembly line.  Honda considered a flat topology linking the whole Yorii plant in a single network, but given the possibility that a single failure could stop the entire plant’s network, they decided on multiple networks.

Constructing individual networks by application however would not only mean a more complex system but increased introduction and operation costs. Additionally, from the perspective of spreading know-how from the Yorii “mother factory” to other factories, something not only sturdy but simple in construction was preferred.

Whilst considering the system architecture, the team also identified two functions essential for the network. One was the centralized “visualization” of FA control devices, where the target was an environment in which FA control device setup, monitoring, failure detection and so on could be centralized through the network.

The other essential function was the communication of safety signals. When a worker enters a prohibited area or approaches a robot, safety considerations mandate a sensor for detection and a production facility stop (interlock). However, the traditional practice of using relays to configure a hardware based safety circuit presented the issue of serious time loss during line expansions and changes. As a result, they decided to incorporate safety signals into the network, aiming for a structure that would allow flexible line changes.

Ethernet based field network

Based on these needs, Yorii considered Mitsubishi Electric’s CC-Link IE Field Network. With CC-Link IE Field, a single Ethernet cable not only allows communication of control information for PLCs and controllers, but also maintenance and safety information from the connected FA devices.

Compatibility with factory automation control devices was also an important point. In order to fulfil the projected production numbers, the vehicle body assembly line needed to be maintained at a near constant 100 percent operating rate, requiring reliability and guaranteed performance from the FA control devices.

Mitsubishi Electric automation devices and CC-Link IE Field Network were selected for vehicle body assembly line, press shop, resin moulding process, vehicle body painting line, and other production areas. The CC-Link IE Field Network is an Ethernet based field network following the physical and data layers as defined by IEEE 802.3 (1000BASE-T) supported by the CC-Link Partner Association (http://www.cc-link.org/jp/).

As well as covering high-speed I/O and control of distributed controllers, it offers flexible network topology types such as star and ring, allowing great freedom in the arrangement and configuration of connected devices. In addition, it supports management (setup and monitor) and maintenance (monitoring and failure detection) of controller devices, and features a safety communication function allowing sharing of safety information among multiple safety PLCs.

Batch management of 50 PLCs for improved operating efficiency

CC-Link IE Field achieved the enhanced visualisation that Honda required, so when there is a problem with the equipment or FA control devices, the diagnostic functions of network help them locate the problem faster.

The vehicle body assembly line alone uses over fifty Mitsubishi Electric PLCs and the centralised overview of the line indicates any trouble happening when a necessary signal isn’t being received, making operation management efficiency higher and reducing recovery times.

With regard to line expansion and safety information, it is as simple as connecting a LAN cable to a vacant port on the CC-Link IE Field Network and the interlock can be added immediately in Mitsubishi Electric’s Safety PLC, reducing the workload considerably.

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