Myth 1: Application programming for modern safety PLCs is so easy that anyone can do it.
With drag-and-drop interfaces, function blocks and some training, you would think that almost anyone could program a PLC. But translating critical safety logic into a PLC application program requires close cooperation among programmers, process control engineers, and operations and maintenance personnel to ensure that the application program supports plant operation, as well as safe operation.
A program specification should be developed and approved prior to PLC programming. Some PLCs have tools that translate the program as written into an engineering document. This is great for debugging the program, but it is not the same as programming and validating the system operation per an approved specification. Through a debugging exercise, you can obtain a program that under certain test conditions will do what you intend, but this program can have significant hidden problems that will not be seen until conditions change. A program with latent bugs can negatively impact system reliability and risk reduction. Disorganized and complex programming can yield an application program that’s difficult to understand, properly test and safely modify.
SIS-TECH has experience with all major brands of PLCs. Whether Emerson, Honeywell, Siemens, Allen-Bradley, Yokogawa, HIMA, Triconex, or any other PLC, SIS-TECH can execute turn-key projects in critical control, alarm, interlock and SIS applications. For more information on SIS-TECH’s independent engineering services, contact Eric Randecker, firstname.lastname@example.org or 832-434-7307.