PLC to cloud
data collection
Read the registers your PLC already exposes over Modbus and publish them to the cloud with time and status. The PLC program stays exactly as it is, and the register list is managed from the cloud application.
THE PROBLEM
The PLC knows everything about the machine, and shares it with nobody
A PLC holds the most useful data in the plant: cycle counters, step numbers, alarm words, setpoints and the state of every interlock. Most of it lives in holding registers that only the HMI on the front of the panel reads. Managers and remote engineers see it when someone walks over and looks.
The usual ways out are heavy. A SCADA licence for a handful of tags, a PC in the panel running an OPC server, or a change to the PLC program to push data out, which means re-testing a machine that already works. IT teams are also cautious about opening a path from the cloud into the control network.
Reading registers over Modbus avoids most of this. The PLC keeps running its logic, the gateway polls the registers you agree on, and data leaves the site over an outbound encrypted connection.
HOW WE SET IT UP
From register list to cloud dashboard
Most of the work is agreeing which registers matter. The gateway does the rest.
Agree the register list with the programmer
We work from the PLC programmer's tag list or Modbus map: addresses, data types, scaling and word order. Only the registers you approve go into the gateway configuration.
Connect on RS485 or Ethernet
Serial PLCs connect over RS485 with Modbus RTU. PLCs with an Ethernet port connect over Modbus TCP. The gateway can poll as master, or sit as a slave where the PLC or SCADA already owns the bus.
Map registers in the cloud application
Integrators name each register, set its scaling and choose how often it is read, all in the cloud application. When the PLC program changes, the map is updated remotely.
Publish with time and status
Readings are sent over MQTT with TLS 1.2 to RIOD Live or your own server. Each set carries its time, together with the run and fault status bits you chose to read.
AT A GLANCE
PLC data collection in brief
- What is read
- PLC holding and input registers, coils and status bits, with the time of each reading
- Hardware
- RS485 Modbus IoT gateway, Modbus RTU over RS485 and Modbus TCP over Ethernet, master or slave
- Connectivity
- Ethernet, Wi-Fi or 4G, chosen per site. MQTT over TLS 1.2
- Power
- 12 V adapter from the panel supply, in a plastic, metal or custom enclosure
- Where data goes
- RIOD Live, or your own server, with API access, PDF and Excel exports with audit trails, and AI access through MCP
- Configuration
- Register map set by the integrator in the cloud application
- PLC compatibility
- Confirmed per model: built-in Modbus TCP, an RS485 port with Modbus RTU, or a Modbus communication module
FAQ
Questions buyers ask us
Do we need to change the PLC program to send data to the cloud?
In most cases, no. If the PLC exposes its data over Modbus, the gateway reads the existing registers and the logic stays untouched. If some values are internal, the machine programmer can copy them into a block of Modbus registers, which is a small, contained change.
Which PLCs can be read over Modbus?
Any PLC with a Modbus RTU serial port, a Modbus TCP Ethernet port, or a Modbus communication module. We confirm the interface for each PLC model during the survey, together with the register map and data types.
Is it safe to connect a PLC to the cloud?
Yes, when the gateway reads the PLC locally and only sends data outward. It publishes over MQTT with TLS 1.2, so the connection starts from inside the plant. The register list is limited to the points you approve, and read access is the normal configuration for monitoring.
Can the PLC data go to our own SCADA or historian?
Yes. Data can stay in RIOD Live, go to your own server, or be passed to a SCADA, historian or MES through an API.
Want your PLC data in the cloud?
Send us the PLC model and the registers you need. We will confirm the connection and how quickly your integrator can have it reporting.