In the automation industry, engineers strive every day to advance their process and products. Engineers have to select components, learn and use many tools to construct their automation systems, and support the systems in production. More importantly, to be successful and competitive, they are faced with many challenges to achieve higher throughput and ease of use within budget and time limitations.
Motion control systems play a critical role in all automation systems, and directly enable and dictate the functionality and speed. This article presents some ideas about what engineers seek and need to build their automation systems to achieve their goals. Connecting the customer needs and the automation system supplier empowers both.
Customers need advice about what capabilities and functionalities to consider during their research and decision making. Automation suppliers need to listen to customer needs and continuously improve the solutions.
What the Customer Needs
Customers’ needs are diverse and spread over the following areas: architecture, real-time system, network, motion controller, servo, programming, language, sizing, tuning, troubleshooting, simulation, and tools. There are many questions from customers regarding motion control.
For example, considering a typical motion system consists of three layers – the motion controller, the network, and the servo – what characteristics are needed in these areas, and what software tools will deliver the highest performance and ease of use?
What motion capabilities does the controller need to have? What actuators are supported? Servo (rotary and linear), ac drives, steppers, and some applications need robotic integration. What level of integration is required with this platform – communications, sensors, vision, safety, and diverse different devices?
The System Approach
Using a system approach (Figure 1) in automation systems, the following items are important for customers, but can have different weight for different customers.
Architecture is crucial in the automation system, as it immediately illustrates and makes tangible what the automation system can deliver and its limitations. Complementing the system architecture is the control network or networks supported by the platform. The network achieves the main portion of the architecture and enforces allowable devices, configurations, update speeds, and connectivity.
Another two important elements for the automation system to deliver and execute the desired performance are the motion capabilities and the servo capabilities. These are the two elements that deliver the performance through the network.
Every system requires integration and control with a variety of devices and systems. Customers need a selected platform to not only enable integration, but to achieve this easily and in a timely manner. Finally, from concept to production, customers need the programming, development, and support tools.
Customers need to spend most of their valuable time working and achieving their automation system with the desired performance, functionality, and time frame. When the development, hardware, software, or support tools take more of their time, it delays the time to market, narrows the application focus, and reduces their margins. By spending more time on their application and less time on the tool itself, customers can accelerate and advance their machines. That’s why customers demand robust, intuitive, easy-to-use software tools that can implement their ideas. Table 1 lists different tasks customers would spend their time on while dealing with the automation systems.
Motion System Architecture
Much of the motion system architecture is shown in Figure 2. The motion controller or the controller runs the user application and generates motion functionality. It then communicates the motion profile data to all axes through a real-time deterministic network. The network connects the machine devices in line, star, or mixed topology with the controller. All real-time profile generation, coordination, and synchronization are performed by the controller. The controller generates the profile for each servo and receives feedback.
Motion System Overview
Typical motion control consists of these three layers: the controller, the network, and the actuator (Figure 3). The performance and update rates of each layer are critical to deliver the system, combined with the capabilities and algorithms in the controller and the servo drive.
A customer building an automation machine has diverse needs from the motion control. Also, different machines might use different subsets of the full list of capabilities. But adopting a particular automation platform determines foreseeable capabilities. In the automation industry, different automation suppliers would cover many of these capabilities (Table 2).
A motion network offers many advantages over the previous motion generation that used analog or discrete wiring. Using a digital network allows distribution of devices, noise elimination, reductions in wiring cost, configuration, setup, tracing, tuning, and troubleshooting by means of communication with the controller only (Table 3).
Motion Programming and Controller Features
This section covers capabilities and features needed in the servo system. However, machines usually have many actuator types in addition to servo — for example, ac drives, steppers, pneumatic, or hydraulic actuators. The servo and its performance is the delivery point for automation (Table 4).
Customers spend the major portion of their time working in the development software tool. A comprehensive, inclusive development tool would allow customers to perform configuration, setup, programming, debugging, tuning, tracing, simulation, and troubleshooting. Support of the IEC 61131-3 programming standard, with the different languages and support of the PLCopen standard, makes it easy for a customer to exchange, reuse, and capitalize on their training investment. Customers need to have the capabilities to execute multiple programs and to modularize their programming by creating custom function and function blocks and libraries. Additionally, they need code protection and security. Sometimes customers need to run pre-developed and tested programs or a portion of code — for example, written in C or C++ — with their expertise in the industrial controller in real time. This is an added flexibility and might help the customer implement advanced mechatronics solutions.
In developing and maintaining a motion system, many factors are important and needed. The items listed in Table 5 represent some of these.
There are many components, features, and capabilities in an automation platform. A customer needs to have an automation platform that meets their current needs, allows future expansion, saves them time on development and maintenance, and enables them to achieve their goal and become more competitive.
This article was written by Dr. Atef T. Massoud, Motion and Servo Engineer with Omron Automation and Safety, Hoffman Estates, IL. For more information, Click Here .