Design Standards

First and foremost, Wheatland Systems, Inc. strictly adheres to the standards provided by our clients. Most of these standards include strict monitoring by DOT and other government agencies. 

In lieu of client PLC and HMI specifications, Wheatland typically recommends adherence to IEC 61131-3 standards.

IEC 61131-3 is an international standard first published in December 1993 by the IEC. It is the third publication in the series IEC 61131. The current (second) edition was published in 2003. This standard defines two graphical and two textual PLC programming language standards:

· Ladder Logic (graphical)

· Function Block Diagram (graphical)

· Structured Text (textual)

· Instruction List (textual)

The standard also defines both graphical and textual Sequential Function Chart elements to organize programs for sequential and parallel control processing.