plc cpu modules in the PLC control system design methods

First, the most important issue to mention the programmable controller technology is used in automatic control engineering , how to use a comprehensive knowledge learned in front of the point , according to the Nanda plc controller manufacturers  actual requirements of reasonable engineering combined into the control system , introduced in this control system consisting of a programmable controller general methods.
Second, the basic steps programmable controller system design 1. The main contents of the system design ( 1 ) to develop control system design specification. Technical conditions generally in the form of design task to determine which is the basis for the entire  Nanda cpu modules plc design ; ( 2 ) select the form of electric drive and motor , solenoid valve actuator ; ( 3 ) PLC selected models ; ( 4 ) the preparation of the PLC input / output allocation table or draw input / output terminal wiring diagram ; ( 5 ) to write software specification according to the system design requirements, and then use the appropriate programming language ( commonly ladder ) program design ; ( 6 ) understand and follow users cognitive Nanda plc digital input  psychology , attention to human-computer interface design , enhance rapport between man and machine ; ( 7 ) console design , electrical cabinets and non-standard electrical component parts