Engineers have multiple options when it comes to designing, installing, networking and configuring automation assets. However, as technology has evolved, becoming even more powerful, the engineer's job has become commensurately more complex. It is for this reason that Rockwell Automation has developed Integrated Architecture for use in both its high-level and midrange automation platforms.
Integrated Architecture has been created to serve as a foundation upon which flexible and scalable automation, motion, safety and process systems can be built. Its primary features include: functionality and scalability to suit a full range of automation applications and sizes; EtherNet/IP, a single IT-friendly communication and control network; the delivery of real-time actionable information; and knowledge integration.
Key technologies that take advantage of Integrated Architecture include: Logix programmable logic controllers (PLCs) and programmable automation controllers (PACs), scalable controllers with a common control engine and development environment; Kinetix high-performance motion control systems; Stratix managed networks; View visualisation products and, of course, the aforementioned PowerFlex variable-speed drives.
With the introduction of dual-port Ethernet capabilities into the latest PowerFlex models, Rockwell Automation has defined a new level of functionality, while actually decreasing complexity. Device Level Ring (DLR) is a network technology that takes advantage of embedded-switch functionality in automation devices, such as I/O modules, PACs and, in this instance, variable-speed drives.
While a network- or switch-level ring topology provides resilience to the network infrastructure, DLR technology adds device-level network resilience. So, how does this work?
When a DLR detects a break in the ring, it provides alternate routing of the data to help recover the network at extremely fast rates. Indeed, a 50-node DLR network can recover in less than 3ms. During this time, the connection between the PAC and the I/O device is not interrupted. Enhanced diagnostics built into DLR-enabled products also identify the point of failure, helping to speed maintenance and reduce mean time to repair.
In addition to superior network recovery performance, DLR technology helps simplify network architecture while still providing the flexibility to connect and coexist with other network topologies. Multiport EtherNet/IP devices equipped with DLR technology connect directly to neighbouring nodes and form a ring topology at the end devices. DLR offers many other advantages.
Simplified installation is possible because the Ethernet cabling is a daisy chain drive-to-drive; this in itself allows a linear topology that removes the necessity for an external switch in the network. The Linear topology provides the network with more distance because each daisy chain drop is another Ethernet link with the full stretch of the copper cable allowed between each node as opposed to a traditional centre point star configuration using external switches. External switches and linear topologies may be mixed in an architecture.
By joining the two ends of a linear daisy chain network, you create a high availability ring. Rings may also be joined to external switch networks. This peer-to-peer architecture also reduces the physical amount (and therefore cost) of cabling and often avoids it being routed inside trunking with other power cables, minimising any potential interference.
Set up is also more straightforward because the ring only requires two ports on the managed switch, meaning configuration of the switch can be simplified. This new dual port EtherNet/IP connection is also compatible with Automatic Device Replacement (ADC) - a feature that could benefit many customers, helping them to maintain their plant's availability. Rapid recovery from a fault or failure is more important than ever to help increase machine uptime and productivity.
Physically plugging cables into the correct socket is the easy part; it is the network configuration that worries a lot of people. Traditional network-based equipment is not really fully plug-and-play; there might be basic handshaking but in most instances you have to do manual configuration of both the device and the PAC/server.
If for some reason you then have to replace the device, you have to go through all this configuration again, such as allocating the network IP address and making sure that the firmware is compatible.
With this new ADC technology, as well as offering simpler cabling, IP addresses can be automatically allocated when used in conjunction with a Stratix managed switch and any firmware changes can be automatically flashed over the network. What is more, drives (or indeed any other device on the EtherNet/IP network) can be automatically configured with the correct parameter set.
This is the strength of the totally integrated system approach. It's not just the drive; it is a combination of the control system as well. Logix is set up in such a way that it can support this approach using specific add-on profiles for the drive within the Logix programming environment – that’s genuine plug-and-play.
Information flow is also enhanced; manufacturing data can be seamlessly communicated in real time to various levels of an organisation, with no additional complexity. Getting real-time information at the right time and at the right levels of the manufacturing environment helps to improve just about every facet of a plant's operations.
Jonathan Smith is field business leader – drives, at Rockwell Automation