DSDO120 ABB

Graphical instruction structure:The program is expressed graphically,and the instructions are composed of different graphic symbols,which are easy to understand and remember.The software developer of the system has compiled the independent computing functions required in industrial control into symbolic graphics,and users can combine these graphics according to their own needs and fill in the appropriate parameters.In the logic operation part,almost all manufacturers use the ladder diagram similar to the relay control circuit,which is easy to accept.For example,Siemens also uses the flow chart of the control system to represent it.It uses the graphic symbols of binary logic elements to express the control relationship,which is very intuitive and easy to understand.More complex arithmetic operations,timing counts,etc.are generally represented with reference to ladder diagrams or logic component diagrams.Although they are not as symbolic as logic operations,they are also popular with users.

图形式指令结构：程序由图形方式表达，指令由不同的图形符号组成，易于理解和记忆。系统的软件开发者已把工业控制中所需的独立运算功能编制成象征性图形，用户根据自己的需要把这些图形进行组合，并填入适当的参数。在逻辑运算部分，几乎所有的厂家都采用类似于继电器控制电路的梯形图，很容易接受。如西门子公司还采用控制系统流程图来表示，它沿用二进制逻辑元件图形符号来表达控制关系，很直观易懂。较复杂的算术运算、定时计数等，一般也参照梯形图或逻辑元件图给予表示，虽然象征性不如逻辑运算部分，也受用户欢迎