【正文】 function available on the main program for didactic purposes, the user gives the signal to execute the step.?LCD display, which shows the status of the system, values of inputs, outputs, timer and statistics of the sequence execution.?Beep to give important alerts, stop, start and emergency. ? Leds to show power on and others to show the state of inputs and outputs. . Security To make the final application works property, a correct configuration to execute the steps in the right way is needed, but more then that it must offer solutions in case of bad functioning or problems in the execution of the sequence. The controller offers the possibility to configure two internal virtual circuits that work in parallel to the principal. These two circuits can be used as emergency or reset buttons and can return the system to a certain state at any time [2]. There are two inputs that work with interruption to get an immediate access to these functions. It is possible to configure the position, the buttons and the value of timeout of the system. . User interface The sequence of strings can be programmed using the interface elements of the controller. A Computer interface can also be used to generate the user program easily. With a good documentation the final user can use the interface to configure the strings of bytes that define the steps of the sequence. But it is possible to create a program with visual resources that works as a translator to the user, it changes his work to the values that the controller understands. To implement the munication between the puter interface and the controller a simple protocol with check sum and number of bytes is the minimum requirements to guarantee the integrity of the data. . Firmware The main loop works by reading the strings of the steps from the EEPROM memory that has all the information about the steps. In each step, the status of the system is saved on the memory and it is shown on the display too. Depending of the user configuration, it can use the interruption to work with the emergency circuit or timeout to keep the system safety. In ,a block diagram of micro controller main program is presented.5. Example of electropneumatic system The system is not a representation of a specific machine, but it is made with some mon movements and ponents found in a real one. The system is posed of four actuators. The actuators A, B and C are double acting and Dsingle acting. Actuator A advances and stays in specified position till the end of the cycle, it could work fixing an object to the next action for example (Fig. 5) , it is the first step. When A reaches the end position, actuator C starts his work together with B, making as many cycles as possible during the advanc。附錄二 英文文獻(xiàn)Programmable designed for electropneumatic systems controllerThis project deals with the study of electropneumatic systems and the programmable controller that provides an effective and easy way to control the sequence of the pneumatic actuators movement and the states of pneumatic system. The project of a specific controller for pneumatic applications join the study of automation design and the control processing of pneumatic systems with the electronic design based on microcontrollers to implement the resources of the controller.1. IntroductionThe automation systems that use electropneumatic technology are formed mainly by three kinds of elements: actuators or motors, sensors or buttons and control elements like valves. Nowadays, most of the control elements used to execute the logic of the system were substituted by the Programmable Logic Controller (PLC). Sensors and switches are plugged as inputs and the direct control valves for the actuators are plugged as outputs. An internal program executes all the logic necessary to the sequence of the movements, simulates other ponents like counter, timer and control the status of the system. With the use of the PLC, the project wins agility, because it is possible to create and simulate the system as many times as needed. Therefore, time can be saved, risk of mistakes reduced and plexity can be increased using the same elements.A conventional PLC, that is possible to find on the market from many panies, offers many resources to control not only pneumatic systems, but all kinds of system that uses electrical ponents. The PLC can be very versatile and robust to be applied in many kinds of application in the industry or even security system and automation of buildings.Because of those characteristics, in some applications the PLC offers to much resources that are not even used to control the system, electropneumatic system is one of this kind of application. The use of PLC, especially for small size systems, can be very expensive for the automation project.An alternative in this case is to create a specific controller that can offer the exactly size and resources that the project needs [3, 4]. This can be made using microcontrollers as the base of this controller. The controller, based on microcontroller, can be very specific and adapted to only one kind of machine or it can work as a generic controller that can be programmed as a usual PLC and work with logic that can be changed. All these characteristics depend on what is needed and how much experience the designer has with developing an electronic circuit and firmware for microcontroller. But the main advantage of design the controller with the microcontroller is that the designer has the total knowledge of his controller, which makes it possible to control the size of the controller, change the plexity and the application of it. It means that the project gets more independence from other panies, but at the same time the responsibility of the control of the system stays at the designer hands2. Electropneumatic systemOn automation system one can find three basic ponents mentioned before, plus a logic circuit that c