Modbus TCP Gateway iNut PC — 9 Features That Turn an Industrial Gateway into a Data Orchestration Hub

The Overview tab is the coordination hub — showing all listening servers, connected clients, request/response counts, online/offline status, and the last communication timestamp. Everything updates in realtime, no page refresh needed.

Operations engineers can look at a single screen and instantly know: how many devices the gateway is serving, which PLCs are active, and which data streams are interrupted.

• Live status realtime
• Server list
• Client list
• Request counter
• Last seen timestamp

iNut PC can act as a Modbus TCP Slave — the customer's SCADA, HMI, or DCS connects and reads IEC104 data using the familiar FC03 command. No need to upgrade legacy SCADA, no need to change PLC logic.

Configuring a server only requires selecting the port (default 502), the slave ID, and enabling/disabling it. The system supports multiple servers running in parallel, each serving a separate network segment.

• Multi-server
• Custom port
• Slave ID config
• FC01/02/03/04
• Enable/disable per server

Acting as a Modbus TCP Master, iNut PC automatically polls data from PLCs, energy meters, inverters, sensors — any device that supports Modbus TCP or RTU-over-TCP. Each client is configured individually: IP, port, slave ID, the list of registers to read, and the polling interval.

Once read, the data is stored in internal memory, ready to be bridged to IEC104, pushed via MQTT, or served to SCADA through the Modbus Server.

• Multi-client
• Custom polling interval
• FC03/FC04/FC01/FC02
• Auto-reconnect
• RTU over TCP

This is the core feature that sets iNut PC apart from ordinary Modbus gateways. Bridge Mapping enables two-way mapping between IOA addresses (IEC104) and Holding Registers (Modbus) — IEC104 measurement points from RTUs/substations automatically appear at the corresponding Modbus register.

A tree-view interface visualizes the entire mapping: source IOA → target register, data type, scale factor, and sync status. Mappings can be added or removed without restarting the service.

• Bidirectional mapping
• Tree view UI
• Scale factor
• Hot-reload
• Bulk import/export

iNut PC has a built-in MQTT Publisher — pushing Modbus data to any MQTT broker (Mosquitto, HiveMQ, AWS IoT, Azure IoT Hub, etc.) on a configured interval or on-change. No middleware, no external Python scripts required.

Configuration includes: broker host, port, topic prefix, QoS, interval, and username/password authentication (masked on screen for security). Data is published as standard JSON, easy to parse for any upstream system.

• Interval / on-change
• JSON payload
• QoS 0/1/2
• TLS support
• Multi-topic

Stats Counter is a dedicated data accumulation module for energy measurement: counting kWh pulses from electromechanical meters, integrating power values over time, and logging readings by shift/day/month. Especially useful for factory power consumption monitoring systems.

The FTP Report module automatically exports CSV files on a schedule (hourly/daily/weekly) and uploads them to the customer's FTP server — no need for engineers to manually collect the data.

• Pulse counter
• kWh integration
• Shift/day/month log
• FTP auto-export CSV
• Schedule backup

The Timer Scheduler module allows scheduled FC05/FC06 writes to a Modbus device's coil or register — no intermediary PLC needed, no ladder programming required. Turn off pumps at 23:00, turn on lighting at 6:00, shed load on weekends... all configured through the web.

Each timer includes: the target client, register/coil address, ON/OFF value, execution time, and day-of-week repetition. An internal RTC ensures timers run precisely on schedule even without an internet connection.

• Daily / weekly schedule
• FC05 coil write
• FC06 register write
• Internal RTC
• Multi-timer

Integration engineers usually need to install Modbus Poll, Modbus Slave Simulator, or other dedicated PC tools to test devices in the field. iNut PC has a built-in Modbus Poll Tool on the web — just a browser, nothing else to install.

Select a client, enter the function code, starting address, and register count, then click Poll — results are shown instantly as a hex/decimal table. Supports FC01, FC02, FC03, FC04, FC05, FC06, FC15, FC16.

• Web-based, no tool installation
• FC01–FC16
• Hex + Decimal view
• Batch read
• Write test

When a Modbus communication error occurs, viewing the raw frame is essential. The Logs & Raw JSON tab displays all requests/responses in real time: function code, slave ID, register address, returned data, and exception codes if any errors occur.

Logs can be filtered by client and level (info/warning/error), and exported as JSON for offline analysis. This is an essential tool when commissioning new equipment or troubleshooting intermittent errors in the field.

• Realtime log stream
• Raw hex frame
• Exception code decode
• Filter by client
• Export JSON