Function block programming `avoids the snags`

Omron has adopted a new strategy for function block (FB) programming of its CJ1 and CS1 PLCs which, it says, will offer increased flexibility without compromising performance. The latest versions of the PLCs offer IEC 1131-3-compliant structured text programming in user-defined function blocks, in addition to the standard ladder logic.

Although FB programming can add flexibility to a PLC, it often comes at a cost in terms of memory, resulting in decreased performance because of the way that data transfers to and from the function blocks are managed in firmware. Omron says that the new versions of its PLCs avoid this problem by using a new hardware architecture based on the company`s "multilingual control engine".

The new CPUs are backwardly-compatible with earlier models allowing users to migrate to them without changing any code. Omron is offering a growing library of predefined and tested function blocks which can be configured using drag-and-drop techniques, cutting development times, and easing maintenance.