4 Critical Requirements for PC-Based Motion Control
| By: Dipesh Mukerji, Vice President Marketing & Strategy
A number of trends and reliability concerns affect the controller choices engineers make in regards to PC-based motion control systems and machine control systems. The PC has become the common control device in manufacturing industries and processes, replacing the CNC and the PLC in many industrial applications. It contains software and hardware into a single software package. The software package is known as soft logic PLC or soft PLC.
Therefore, choosing the ideal controller for applications that require PC-based motion control is quite straightforward. The difficulty arises when trying to choose the ideal PC-based motion controller for applications involving discrete control, motion control and human machine interfaces. To get an ideal PC-based solution that fulfills functional requirements, engineers must consider the following requirements.
Since there is no universally documented definition for openness, engineers are required to determine the level of openness that will work for their industrial applications. An open soft motion control system should allow engineers to determine the ideal machine control programming languages to use, the best PC hardware, motion control devices, human machine interface devices, output and input modules. All these devices should work together seamlessly if you choose the right level of openness.
A number of manufacturers produce I/O device networks that operate under most systems. Though Windows software is the de facto standard for HMI, motion control devices and machine control programming languages have yet to become completely open.
Economics is a major factor that engineers must consider before deciding how to enhance their PC hardware openness. In a PC-based motion control system, hardware ought to be selected based on the cost, flexibility, microprocessor power and packaging. Microprocessor choices range from 200 MHz Pentium to 386 microprocessor. Microprocessor selection is based on the operating system requirements, HMI requirements and the tasks your PC is set to perform.
PC hardware choices include commercial desktop versions and ruggedized industrial versions. Due to its special features, an industrial PC costs more than the regular desktop model. Commercial PCs are designed to run more hardware and software packages. Small PCs that contain solid state hard drives are used in applications that have no ventilation or control cabinet cooling, saving costs of cooling additions and special enclosures.
Ease of use
An ideal PC-based motion control system should be flexible and easy to use to allow simultaneous use of run-time control system debug tools and configuration setup software. For instance, an easy-to-use system should effectively run hardware-based motion controllers while running a software-based control program.
Before investing in a PC-based motion solution, you must ensure that it provides a reliable watchdog hardware output. Software watchdogs that can operate between hardware motion control and software control should be a major consideration. Safety considerations allow motion controllers to perform an easy shutdown in case the PC CPU develops a problem.
It is up to engineers to select the right PC-based motion control system that works flawlessly with their industrial applications. Consider the factors above to make the right choice for your organization.