Embedded Edge Calculation Coprocessing for PLCs

Offload IF97 steam/water, mass flow, and energy calculations to a dedicated module—connected via Modbus RTU over RS‑485 and mapped directly into your PLC holding registers.

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Helix Energy Transfer edge coprocessing module

On-edge coprocessing for critical energy calculations

The Helix Energy Transfer module is a DIN-rail mounted embedded coprocessor designed to sit beside your PLC and handle intensive thermodynamic and flow calculations. It exposes a clean Modbus RTU RS‑485 interface, presenting results as PLC-friendly holding registers.

  • Deterministic: Fixed-cycle calculation engine for stable scan times.
  • Configurable: Critical constants and setpoints written via Modbus registers.
  • Industrial: RS‑485, robust terminals, and status indicators (TX/RX/ON).

Key capabilities

  • IF97 steam/water property calculations
  • Mass flow and volumetric flow calculations
  • Energy and BTU calculations for thermal systems
  • Register-mapped configuration and diagnostics

Calculation engines on board

Three primary calculation engines run on the module, each exposing inputs, constants, and results through a structured holding register map.

IF97 steam/water calculations

Implemented according to IAPWS IF97 formulations, the module computes key thermodynamic properties such as enthalpy, entropy, density, and specific volume from pressure and temperature inputs.

  • Inputs: Pressure, temperature, phase region selection.
  • Outputs: Enthalpy, entropy, density, specific volume, saturation properties.
  • PLC mapping: Each property exposed as a dedicated holding register pair.

Mass flow calculations

The mass flow engine converts sensor inputs—such as differential pressure, line pressure, and temperature—into real-time mass and volumetric flow values for water and compatible fluids.

  • Inputs: ΔP, static pressure, temperature, meter factor.
  • Outputs: Instantaneous mass flow, volumetric flow, totalized flow.
  • Use cases: Water flow measurement, steam lines, and process utilities.

Energy and BTU calculations

The energy engine computes BTU and other energy metrics by combining flow, temperature, and fluid property data—ideal for chilled water, hot water, and steam energy metering.

  • Inputs: Supply/return temperatures, mass flow, fluid constants.
  • Outputs: Instantaneous energy rate, accumulated BTU, kWh-equivalent.
  • Applications: Plant energy monitoring, billing, and performance tracking.

Modbus RTU RS‑485 integration

The module connects directly to your PLC over RS‑485 using Modbus RTU. All configuration, constants, and results are exposed as a structured holding register map, ready for your ladder logic or function blocks.

  • Register map: Inputs, constants, and results grouped by calculation engine.
  • Diagnostics: Status words, error codes, and communication counters.
  • Scalability: Multiple modules can share a bus with unique slave IDs.

Typical PLC workflow

  1. Write constants: Load critical constants into configuration registers.
  2. Feed inputs: Map sensor values into input registers each scan.
  3. Read results: Consume enthalpy, flow, and BTU results from output registers.

Helix Energy Transfer

Development of the embedded edge‑calculation platform is ongoing, and additional technical details—such as integration concepts, register structures, and example applications—will be shared as they mature.

This section will continue to evolve as the project progresses. Those exploring PLC‑connected calculation modules or similar architectures are welcome to check back for updates as new information becomes available.