Cathedral Essence - ASHRAE Guideline 36 Controls Development for Building Automation OEMs
Building automation outgrows ladder logic fast. We write object-oriented Structured Text for IEC 61131-3 PLCs — control software that's modular, testable, and maintainable across a building's entire operating life, including the HVAC and life-safety systems that can't be an afterthought.
OO-ST
IEC 61131-3 object-oriented ST
BACnet
Modbus / KNX interoperability
ASHRAE G36
Guideline 36 sequence compliance
BMS
Life-safety system integration
One Mission Across Verticals
Scalable Control logic built like software.
01
OO-ST Controller Software
Function blocks and class-based structures in Structured Text that turn repetitive control sequences into reusable, versioned modules.
02
BMS & Protocol Integration
Building management system integration across BACnet, Modbus, and KNX, tying HVAC, lighting, access, and life-safety subsystems together.
03
OT Network & Controls Architecture
Controls architecture built around ASHRAE Guideline 36 sequences of operation from the start, not retrofitted after commissioning.
Problems Essence Solves
Energy Efficiency Challenges
Environmental and Sustainability Pressures
Embedded Software Complexity
Integration with Modern Platforms
Talent & Organizational Constraints
Our process
We're typically brought in to modernize a legacy ladder-logic install into a maintainable OO-ST codebase. For the purposes of ASHRAE Guideline 36, we provide system models (i.e. SysML, UML, VHDL), libraries, Hardware Abstraction Layers (HAL) and Board Support Packages (BSP) to enable the modeling of the building control domains — HVAC, life-safety, access — as system components with defined interfaces before writing a single function block, so the resulting codebase can outlive the commissioning team.
See our MBSE approachStandards & Frameworks
IEC 61131-3
IEC 61499
ASHRAE Guideline 36
BACnet
Modbus TCP/RTU
KNX