Summary:
General Embedded Vision Platform (GEVP) responds to the needs of typical Industrial Computer (IPC) monitoring applications by providing a vision enabled development platform based on PC-based architectures. The "General" in GEVP represents the essential functions provided by the platform required for standard IPC administration (such as motion control, vision processing and capturing, analog and digital I/O control, RS-232/422/485 support and etc.). "Embedded" describes how the GEVP is well-suited as a central controller for nearly every type of system with its minimum space requirements and exceptional design. "Vision Platform" indicates how system designers can use the specific built-in vision functions to develop vision-related applications. Programmable Logic Controller (PLC), while widely used in the field, are unsuitable for networking and vision applications due to expandability issues and expensive modules. However, the next generation GEVP offers high speed and simple operations at a low costs that easily connects to various data systems (administration systems, HMI, databases, etc.) for efficient performance. This article will discuss the GEVP architecture and characteristics as well as the practical applications and benefits.
GEVP System Architecture:
In a nutshell, a GEVP is actually a PC-based vision solution platform. Therefore, it makes sense to assess it in two separate parts: software and hardware (see Figure 1). Its hardware is comprised of the CPU and I/O interface. CPU and I/O requirements vary from application to application. As for the software, the OS selected is the most important factor to ensure that the controller meets the needs of the application.
CPU:
Because the CPU is the core of the system's hardware, GEVP is built with the application requirements in mind when selecting its CPU. Because industrial computers have been used in a wide variety of applications, from simple digital/analog signal controllers to complicated motion controllers and vision monitoring systems, the computing power it requires can vary greatly. For example, a Pentium-grade CPU would probably be sufficient for typical digital/analog signal or small (1-3 axes) motion controller applications. However, the same CPU would be wholly insufficient for video capturing and monitoring, high resolution image capture and image processing or multi-axis motion controllers and etc. In those cases, a more powerful CPU, such as Pentium III or Pentium M would suffice. Solutions should be built to meet the needs of system developers and not just follow the latest trends. By selecting an appropriate CPU, the cost is kept to a minimal yet meets all the requirements. GEVP is developed under this concept.
Figure 1: GEVP System Block Diagram
Form Factor:
Typical embedded industrial controller applications have space limitations and cannot use standard IPC form factors. In view of this, GEVP was specially designed for compactness and heat dispensation ability. Even though GEVP is small enough to fit in a little box, it still has standard buses (PC-104 (ISA)) to ensure flexibility and expandability for integration with peripheral interface cards.
I/O:
Because GEVP is a general embedded controller, with it's interface and limited space, you may wonder how it is possible for it to meet the needs of so many different types of industries. It is simple! By offering multiple types of I/O interfaces, many different configurations are possible. With such flexibility we are able to meet virtually every application with ease. Some of our popular modules are:
Operating System Selection:
If you liken equate the GEVP hardware to a human body, the Vision part of the GEVP would be the eyes, the I/O would be the ears, hands, and feet; the CPU and bus are the nervous system and the software is the brain, a complex procedure coordinating every operation of the controller. Hence, the importance of the OS is superlative as it is responsible for managing core tasks and resource allocations of the PC. It not only affects future system execution time and efficiency, but also resource requirements during software development for the whole application. Selecting a suitable OS to suit different application requirements is an important topic for system developers. When choosing an OS, several points must be considered, mainly stability, real-time capability, multitasking, human-machine interface (or GUI), memory size and total cost, including application development costs, licensing costs for multiple copies, software engineering manpower, maintenance costs and etc. There isn't, necessarily, a right and wrong or good and bad OS. System developers should look at the overall picture of the application and focus on what provides the optimal solution for the developed system when considering this issue. One OS may work optimally for one application and be slow for another. In this respect, GEVP is compatible with several operating systems, including the ones shown below:
Embedded XP:
Generally speaking, the concept behind the design of Embedded XP is simply a modularized Windows XP. System developers only select the necessary XP components and functions and then organize them together to construct an Embedded XP OS. As for the concept of architecture modularization, system integrators can readily reduce the storage space requirements of Embedded XP to 256MB or lower. The only factor in selecting storage space size is the number of selected function modules required. Because Embedded XP is completely compatible with Windows XP, developers can simply compile controller software in Windows XP, and then copy it over to Embedded XP for immediate use. System developers have no new tools to learn and years of accumulated Windows XP expertise can be directly conveyed, effectively lowering software development costs. The only major issue actually lies in the cost of licensing Embedded XP.
Windows CE:
Examining Windows CE, it is evident that it inherits the Windows GUI. Because Windows CE is designed with embedded systems in mind, its required storage space is much less than Embedded XP. Typically, 64MB of storage space is need for a Windows CE system. However, if necessary, it is possible to use less storage space. Windows CE impressively supports important real-time functions, and holds true to the familiar Windows GUI. Microsoft has tried to keep API naming conventions and development time consistent between Windows CE and Windows XP. However, because Windows CE is based on embedded architecture, unlike Windows XP's desktop system concept, the software development process will still have differences. It is useful for newcomers to the embedded world to keep this in mind. Nevertheless, on a positive note, Windows CE licensing costs, thanks to Microsoft's recent promotions, is much less than Embedded XP.
Linux:
Linux is well known for its stability and free licensing. In server and networking applications, Linux retains 30% of the market. But in the PC-based controller arena, Linux support is still in the early stages of development. One of it's many userability issues is that Linux's real-time ability is not very apparent. Its high level user interface is not common with what most software engineers are accustomed to. As for developmental issues, its numerous kernel versions can create a big headache for engineers. Compared to Windows, finding bugs and performing routine maintenance can prove to be more difficult, not to mention time consuming. However, because Linux systems use open licensing methods, system developers can save a bundle by not having to purchase Windows CE or Embedded XP licenses. From a technology standpoint, as long as the software engineers have experience with kernel development and maintenance, Linux can actually be a very cost-effective solution.
Conclusion:
Following the progression of software, networking and vision technologies, many ideal solutions have been developed. What previously was thought to be impossible is now gradually becoming reality. This has lead to the innovative GEVP (General Embedded Vision Platform) concept, a direct product resulting from recent technology developmental trends. The compact GEVP design is derived from the concept of embedded applications. Its practical applications come from a diverse selection of CPUs (Pentium III to Pentium M) and storage devices (HDD or CompactFlash cards), and a complete line of hardware interfaces (motion control, serial bus, CAN bus, high-speed serial I/O, digital signal control, and remote monitoring modules)-all based on meeting stringent cost and hardware requirements. Additionally, embedded OS technology utilizes familiar Embedded XP, Windows CE, Linux, etc. software development environments. This technology has finally matured. Restrictions of the past are no longer relevant. All that is left to determine is what hardware equipment is the most suitable for your application.
