Function Block Programming Shears Fixed Length Of Feeding Servo Control

Function block(FB) is a basic unit,which standardizes the process function and is an important PLC programming language.FB is provided as the library files by the PLC manufacturers or defined by the users,which can be used repeatedly.Using FB in the PLC program can save much time,cut the design cycle,decrease the wrong codes and improve design quality.Further more,it is helpful to structurize the program and make the program more intelligible.The FB programming used in the fixed-length feeding servo control system of the plate shearing machine was studied in this paper.The main work is as follows.Firstly,the FB programming method was studied based on the OMRON programming software CX-P,including how to define the FB,how to create an instance, how to call the FB and so on.Secondly,three kinds of classic FBs installed in CX-P were researched and the examples were shown,including CPU Unit,Position Control FB and Servo Control FB.Thirdly,the plate shearing machine servo control system for Jiaozhou Ocean Century Corporation was designed using OMRON CP1H and CX-P.PLC sent the pulses to the servo driver based on the length set on the touch-screen and controlled servo system position accurately.Finally,the classic program units,such as dither filter,length to pulse,pulse to length,servo speed,were modularized by FB programming,which made the program's structure more clear and readable,and also easier to debug.The classic parts in the program were designed using FB and debugged separately in this paper.In the end,the whole system was debugged.The system ran stably in the practical application and realized the desired function.The practice proved that FB is an effective programming method.