Poll any Modbus TCP device — PLC, energy meter, VFD, inverter — and display live register values on a real-time SCADA dashboard. Configure tags, set alarms, and view trends. No on-premise server needed.
No credit card · Any Modbus TCP device · Port 502 or custom port
Modbus TCP is the Ethernet variant of the Modbus protocol — the same function codes (FC01–FC16) that engineers have used for 40 years, now transported over TCP/IP on port 502. Every industrial device from PLCs and energy meters to VFDs, solar inverters, and environmental sensors speaks Modbus TCP.
Modbus TCP SCADA is a supervisory system that acts as a Modbus master — it polls each configured device on a set interval, reads holding registers, coils, and input registers, and displays the values on live dashboard screens. When a register value crosses an alarm threshold, the system sends an email or SMS alert and logs the event with a timestamp.
SCADA Cloud's Modbus TCP monitoring is entirely web-based — your SCADA agent runs in the cloud and polls devices accessible via your network. A lightweight edge connector bridges devices on private LANs without exposing them directly to the internet.
Full-featured Modbus TCP monitoring from your browser
Connect to PLCs, energy meters, VFDs, solar inverters, flow meters, temperature controllers, and any other device on Modbus TCP port 502 (or custom port). No driver installation — pure TCP polling.
FC01 Read Coils, FC02 Read Discrete Inputs, FC03 Read Holding Registers, FC04 Read Input Registers, FC05/06/15/16 for write operations. Both 16-bit integer and 32-bit IEEE 754 float tags supported.
Configure polling intervals from 1 second to 60 minutes per device. High-frequency devices (energy meters, flow sensors) get 1s polling while slow-changing parameters use longer intervals to reduce network load.
Apply linear scaling (Gain + Offset) to convert raw register counts to engineering units. Set unit labels (kWh, °C, bar, RPM, m³/h) that appear on all dashboard panels, alarms, and data exports.
Configure high, low, and deadband alarms on any Modbus tag. Email and SMS notifications sent instantly on alarm. Alarm history log with timestamps, values, and operator acknowledgement records.
All register values are timestamped and stored in the cloud historian. Plot trend charts for any time range, export data to CSV, and query historical data via the REST API for external reporting.
Where Modbus TCP SCADA delivers the most value
Eastron, Schneider, ABB, and Carlo Gavazzi energy meters all speak Modbus TCP. SCADA Cloud polls voltage, current, power factor, kWh, and demand registers and displays them on per-meter and site-wide dashboards.
Huawei, SMA, Fronius, and Sungrow inverters expose generation data over Modbus TCP. Connect SCADA Cloud to read DC input power, AC output, fault codes, and daily kWh per string or inverter.
Modern PLCs (Siemens, Mitsubishi, Delta, Kinco) support Modbus TCP server mode. Read production counters, setpoints, and status bits directly from the PLC holding registers without a dedicated HMI panel.
Pump controllers, chiller units, cooling towers, and flow meters with Modbus TCP publish process data to SCADA Cloud. Monitor flow, pressure, temperature, and run hours across all equipment from one screen.
ABB, Danfoss, Siemens, and Schneider drives expose speed, current, fault codes, and runtime hours via Modbus TCP. SCADA Cloud logs all drive parameters and alarms on overload or fault conditions immediately.
Industrial temperature controllers (Eurotherm, Omron, Yokogawa) with Modbus TCP log setpoints and process values. SCADA Cloud triggers alarms on temperature excursions and generates compliance audit trails.
Enter the device IP address, port (default 502), and Unit ID (Slave ID, 1–247). Set the polling interval — 1s for fast devices, 10s for slow-changing parameters. SCADA Cloud tests the connection and confirms it is reachable.
Add tags by entering the register address, function code (FC03 for holding registers is most common), data type (16-bit int or 32-bit float), and scaling. Give each tag a descriptive name and engineering unit label.
Drag tags onto dashboard panels — numeric displays, gauges, trend charts, status lights, alarm lists. Set alarm thresholds on critical registers and configure email/SMS notifications. Historical logging starts automatically.
All four Modbus register types supported in SCADA Cloud tags
| Register Type | Function Code | Address Range | Common Use in SCADA |
|---|---|---|---|
| Holding Registers (4x) | FC03 | 40001–49999 | Setpoints, measured values, counters, parameters — most common for energy meters and drives |
| Input Registers (3x) | FC04 | 30001–39999 | Read-only analog values — temperature, pressure, flow — from sensors and transducers |
| Coils (0x) | FC01 | 00001–09999 | Digital output status — relay states, valve positions, motor run/stop commands |
| Discrete Inputs (1x) | FC02 | 10001–19999 | Digital input status — limit switches, push buttons, alarm contacts, sensor states |
Modbus TCP and Modbus RTU share the same function codes but differ in physical layer and framing. Modbus TCP runs over Ethernet — devices connect via IP address and port 502. There is no CRC in the frame (TCP handles error checking), and multiple masters can connect simultaneously. It is the standard for modern field equipment, energy meters, and network-connected drives.
Modbus RTU runs over serial lines — RS-485 (two-wire, multi-drop) or RS-232 (point-to-point). Legacy PLCs, older energy meters, and many sensors still use RTU. SCADA Cloud supports both via an edge connector that handles serial communication locally and forwards data to the cloud dashboard over HTTPS.
Before connecting your Modbus TCP device to SCADA, use the Modbus Slave Simulator to test your register map offline, or the Modbus TCP Simulator to validate your SCADA master configuration without real hardware. If your PLCs support OPC UA natively, see our OPC UA SCADA page for a subscription-based alternative to polling.
Modbus TCP SCADA is a supervisory control and data acquisition system that uses the Modbus TCP/IP protocol to read register values from PLCs, energy meters, VFDs, and other industrial devices. The SCADA polls each device at a configured interval, reads holding registers, coils, and input registers using Modbus function codes, and displays the values on live dashboard panels. Alarms trigger when values exceed configured thresholds, and all data is logged to a time-series historian for trend analysis and compliance reporting.
SCADA Cloud supports the full set of standard Modbus function codes: FC01 (Read Coils), FC02 (Read Discrete Inputs), FC03 (Read Holding Registers), FC04 (Read Input Registers), FC05 (Write Single Coil), FC06 (Write Single Register), FC15 (Write Multiple Coils), and FC16 (Write Multiple Registers). Both 16-bit integer and 32-bit float (two-register) data types are supported for each read function code.
Yes. SCADA Cloud supports multiple Modbus TCP devices in the same project. Each device has its own IP address, port, and Unit ID configuration. You can add tags from any combination of devices to a single dashboard — energy meter readings from one IP and PLC status registers from another on the same screen simultaneously. There is no hard limit on the number of Modbus TCP devices per project.
In SCADA Cloud's tag editor, each Modbus register tag can have a linear scaling formula applied: Engineering Value = (Raw Register Value × Gain) + Offset. For example, an energy meter register returning 0–4000 for 0–400.0 V uses Gain=0.1, Offset=0. You set the engineering unit label (V, A, kWh, °C, bar, etc.) which then appears on all dashboard panels and alarm messages. 32-bit IEEE 754 float tags are read directly without additional scaling applied.
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No credit card · Any Modbus TCP device · Full features for 60 days
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