Portable IEC 61131-3 Control Applications

Extended Technical Overview

This page expands on the printed technical handout by providing additional detail on control structure, function block availability, and alignment with Open Process Automation and O-PAS™ principles. It is intended for control engineers, system architects, and automation decision-makers.

What the Library Is

The CSI Process Automation Function Library is a modular IEC 61131-3 control library implemented in CODESYS® and developed as part of a structured roadmap toward alignment with Open Process Automation and O-PAS™ principles.

It encapsulates proven regulatory and supervisory control behaviors in a portable, vendor-neutral form that supports multi-vendor deployment, long-term lifecycle independence, and incremental modernization across DCS, PLC, and open control environments.

The library focuses on application portability and control behavior consistency. It does not constitute a complete O-PAS system and does not imply conformance or certification.

Function Block Availability

The table below distinguishes currently implemented function blocks from planned roadmap additions.

Available Now

PID
Control Selector (CS)
Output Splitter (SPLT)
Integrator (INTG)
Analog Input (AI)
Analog Output (AO)
Discrete Input (DIN)
Discrete Output (DOUT)

Coming Soon (Roadmap)

Bias / Gain
Dead Time
Lead–Lag
Ramp Generator
Signal Characterizer
Input Selector
Ratio
Manual Loader
NAMUR PID
Timer

Planned items reflect current roadmap intent and may evolve.

Control Strategy Examples

Cascade Control Loop

Cascade control improves disturbance rejection by separating fast inner-loop dynamics from slower outer-loop objectives, enabling more stable and responsive control across changing conditions.

Override and Constraint Handling

Selector-based constraint handling arbitrates between competing process objectives without modifying underlying controller logic, supporting safer operation during limits, trips, and abnormal conditions.

Alignment with Open Process Automation

IEC 61131-3 used as the canonical application layer
Separation of control logic and execution environment
Application portability across hybrid and evolving architectures
Incremental adoption aligned with O-PAS™ principles
Roadmap-aligned, not positioned as certified

Where This is Used

OPA pilot programs
Brownfield modernization initiatives
Hybrid DCS and open control environments
Multi-vendor automation strategies

About CSI

Collaborative Systems Integration (CSI) is an independent systems integrator specializing in advanced process control and open, vendor-neutral automation architectures.

CSI works with asset owners and integrators to design, implement, and modernize control systems with a focus on application portability, lifecycle independence, and long-term architectural control. Our work spans advanced control, system integration, and incremental alignment with Open Process Automation principles across brownfield and hybrid environments.