I/O and Communication Protocols as Flexible as a Robotic Arm
With PLC-based robotic controls, the hardware, input/output (I/O), and communications protocols available to the PLC are now also available for use with the robotic controls. This is particularly relevant when considering large portions of the proprietary OEM controllers’ I/O communications are primarily for interfacing the robotic controller with the PLC. With this additional communication no longer required, the only interfacing necessary is to the I/O on the robot, which is as simple as any other I/O that you have in your control system. PLC-based robotic controls support a much wider range of I/O hardware and communications protocols than the OEM controllers in order to cater to a wide variety of applications.
A Common Interface
No longer is the teach pendent the primary interface with the robot controller. With PLC-based robotic controls, the Human Machine Interface (HMI) is now the same throughout the system. The alarming system, fault recording, data monitoring, and the other functions that are available to HMI now directly interface with the robot controller. Unique faults and custom operations can be added and changed directly to the robot controller. An HMI interface allows for a much greater application-specific focus, as well as a considerably more agile structure.
Reduced Maintenance and Upgrade Costs
Manufacturing facilities typically integrate many types of equipment into their operations, such as fillers, packers, palletizers, wrappers, and conveyors. There is a tendency in these facilities to favor PLC-based controls for equipment. If each of the manufacturers is allowed to supply their own unique control scheme, the integrated system may be functional, but a nightmare to maintain and upgrade. This is why there are detailed specifications in most manufacturing facility RFPs placing boundaries on the controllers and hardware OEMs use. Using a common control system makes the integrated system much easier and faster to maintain and upgrade, thereby reducing the total cost of ownership (TCO). By integrating the robot controller with the PLC-based controls system, the end user does not incur the additional costs associated with a unique control scheme.
More Robot Choices
Because the OEM controllers have their own unique language and training requirements, many companies that already have industrial robotic solutions tend to prefer the facility’s incumbent robot brand. This has often been an obstacle to selecting the right model of robot from available robot manufacturers, as companies are unwilling or unable to support multiple brands of robots because of the uniqueness of the different controllers. With the advent of PLC-based robotic controls, users are not “locked in” to the brand they chose for their first robot when making future purchases, as the controllers can be common across multiple brands. “Rockwell Automation has focused on providing robot vendors with a range of interface options that best meet our joint customers’ requirements. With standard interfaces, simplified software tools, and world-class robotics partners, we see the world of integrated robotics becoming easier and more affordable,” said Weeks.
Summing it Up
The potential of using PLC-based controls for robots introduces a new set of decisions for robotic integrators. In some cases, PLC controls may not be the best choice. The automotive and other robot-intensive industries, for example, are not likely to convert from OEM controllers due to a large install base and unique application requirements. Additionally, some robotic OEMs do not currently offer a way of provisioning a PLC-based controller.
In making your controller decision, considerations of availability, functionality, and cost must be included in the process. However, in facilities where there is already a large, installed base of PLC machine control with which the robot will need to interface, the familiarity of technical staff with PLC controls over an unknown OEM controller can have significant impact on operational and support costs. A reputable robotic integrator will work to provide a final solution with optimal fit — whether it is PLC or OEM based.
This article was written by Matt Wicks, Vice President, Product Development, Manufacturing Systems, at Intelligrated, Mason, OH. For more information, Click Here.