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.
On-edge coprocessing for critical energy calculations
The Robert Owen Inc. ROI-IOM module is a DIN-rail mounted embedded coprocessor designed to sit beside your PLC and handle intensive thermodynamic and flow calculations.
- Deterministic — fixed-cycle calculation engine
- Configurable — constants written via Modbus
- Industrial — RS‑485 integration
Electrical and mechanical specifications for the ROI-IOM are on the ROI-IOM Series page.
Key capabilities
- IF97 steam/water property calculations
- Mass flow and volumetric flow
- Energy and BTU calculations
- Register-mapped configuration and diagnostics
Calculation engines on board
IF97 thermodynamic calculations
Steam and water properties per IAPWS IF97 — enthalpy, density and specific volume derived on the module from measured temperature and pressure, so the PLC never runs the polynomials.
Mass flow calculations
Instantaneous mass and volumetric flow, density-corrected from the IF97 result rather than assumed at a single design point.
Energy and BTU calculations
BTU, kWh-equivalent and accumulated energy metrics, held in registers the PLC or SCADA system reads on its own scan.
Modbus RTU RS‑485 integration
Configuration, constants, and results are exposed through a structured holding register map. No driver, no gateway, no PC in the loop — the module is another RS‑485 slave on a bus the PLC already speaks.
Three steps to integrate
- Write constants — pipe size, fluid, units, scaling.
- Feed inputs — flow, temperature and pressure registers.
- Read results — energy, mass flow and totals.
Related solutions
Analog signal conditioning
Thermistor, RTD, thermocouple and potentiometer to 4-20 mA for the inputs feeding this module.
Learn more →Modbus RS-485 sensor monitoring
Read the same sensors over Modbus from a PLC, Raspberry Pi, Node-RED or Python.
Learn more →Energy monitoring solutions
Where the calculated energy goes next — recording, trending and reporting.
Learn more →Tell us what you need to calculate
Send the fluid, the sensors and the register map you need and we will specify the module and the mapping. Robert Owen covers sensor signal conditioning, signal processing and data acquisition as one connected service.