SCIL

SCIL — the Supervisory Control Implementation Language, originally the Strömberg Control Implementation Language — is the built-in application programming language of MicroSCADA, a supervisory control and data acquisition (SCADA) platform used to automate electrical substations and power distribution networks. Unlike most languages in this encyclopedia, SCIL was never meant to stand alone: it exists entirely inside one product family, and that product family has been in continuous commercial use for over four decades, first under Strömberg, then ASEA, then ABB, and today Hitachi Energy.

History & Origins

SCIL traces back to Strömberg Oy, a Finnish electrotechnical company based in Vaasa. In February 1982, a small team of software developers there set out to build a new kind of control system. Their motivation was practical: translating customers’ control requirements into FORTRAN (and similar low-level code) for each installation was slow, costly, and error-prone. The team wanted to isolate the “application world” — the specific logic a utility customer needed — from the “basic software world” of the underlying system, so that control applications could be written in a higher-level, purpose-built language instead of general-purpose system code.

The result, operational by 1983, was originally called the Strömberg Control System (SCS). Its application language became known as SCIL, designed as an application-oriented language adapted specifically for control tasks, in a procedural style familiar from FORTRAN-era control programming; later versions layered object-oriented features on top as MicroSCADA’s own object model grew.

Strömberg was acquired by the Swedish industrial group ASEA in 1986. Two years later, ASEA merged with Switzerland’s Brown Boveri to form ABB (Asea Brown Boveri) in 1988, and the Strömberg control system was rebranded MicroSCADA under the new ABB name. In 1989, MicroSCADA received its formal international marketing launch — the “S.P.I.D.E.R.” product launch in Frankfurt — introducing the platform, and with it SCIL-based application engineering, to utility customers worldwide. This 1989 launch is likely why SCIL is often dated to that year, even though the language and its first working system predate it by several years.

Design Philosophy

SCIL was built around a single idea: give control-system engineers, not just professional programmers, a language expressive enough to configure real substation and distribution automation logic without writing system-level code. Because MicroSCADA’s own application layer — its pictures (operator displays), command procedures, dialogs, and much of its configuration — is itself written in SCIL, the language had to be capable enough to build an entire SCADA front end, yet approachable enough for utility engineers to extend and maintain.

Key Features

• Object-aware syntax: SCIL supports a common object syntax for addressing MicroSCADA’s various object types (process objects, pictures, dialogs), reflecting the object concepts added to the platform in later product generations.
• Command-oriented structure: SCIL statements are built from commands, objects, expressions, variables, and names. Distinct command families are distinguished by prefix — picture commands begin with !, graphic/motif commands with ., and “manoeuvre” (procedure control) commands with #.
• Familiar procedural constructs: variable assignment, arithmetic expressions, conditionals, block structure, case statements, and loops, in a style recognizable to anyone who has written FORTRAN or early BASIC.
• Interpreted with a compiler option: SCIL is primarily an interpreted language for interactive and rapid application development, but MicroSCADA also ships a SCIL compiler for performance-sensitive application code.
• Deep platform integration: SCIL code appears throughout MicroSCADA — inside operator pictures, command procedures, Visual SCIL dialogs, and dialog items — making it both the customization language and, in large part, the implementation language of the platform’s own application layer.

Evolution

SCIL grew alongside MicroSCADA’s own product generations. The original SCS-era language supported the procedural needs of early-1980s substation control. As MicroSCADA evolved through the SYS500 and later SYS600 product lines in the 1990s and 2000s, SCIL absorbed more explicit object-oriented capability, letting application code manipulate MicroSCADA’s growing catalog of process, picture, and user-interface objects through a consistent object syntax. Through ownership changes — Strömberg to ASEA, ASEA/Brown Boveri to ABB, and ABB’s power grid business sold to Hitachi in 2020 (forming Hitachi ABB Power Grids, renamed Hitachi Energy in 2021) — SCIL has remained the constant: each new release of MicroSCADA Pro SYS600 has continued to expose SCIL as its native scripting and configuration language.

Current Relevance

SCIL is not a general-purpose language you will find outside MicroSCADA, and it has no independent open-source community, package ecosystem, or standalone interpreter. Its relevance is entirely tied to its host platform, which remains commercially active: Hitachi Energy continues to release new SYS600 versions (with a release noted in 2019, prior to the 2020 divestiture from ABB) and marked MicroSCADA’s 40th anniversary in 2023, citing more than 15,000 delivered systems worldwide. Wherever those installations run, SCIL is still the language engineers use to write and maintain the supervisory control logic.

Why It Matters

SCIL is a reminder that not every influential language was designed to be portable or popular — some were designed to solve one company’s integration problem and then quietly outlived the corporate mergers, rebrandings, and ownership changes around them. Conceived to spare Strömberg’s engineers from writing bespoke FORTRAN for every substation, SCIL has now been the working language of one of the electrical grid’s most widely deployed SCADA platforms for over four decades, surviving the transition from Strömberg to ASEA, from ASEA to ABB, and from ABB to Hitachi Energy without ever needing to leave the product it was built for.