PLC Connectivity
We connect PLCs from any manufacturer and protocol to the Captia unified data layer, making control-layer information reliably available to the rest of your systems, from process historians to dashboards, without altering the control programs.
PLC connectivity: reading control-layer data
PLC connectivity means extracting the data that already lives inside plant controllers and making it available to other systems, from a local historian to the cloud. We connect PLCs from any manufacturer (Siemens, Rockwell, Schneider, Omron and others) to the Captia unified data layer without modifying the control program: variables are read through a communications channel such as an embedded OPC-UA server, Modbus TCP, the Siemens S7 protocol or EtherNet/IP, so the machine keeps running exactly as before. This is deliberately different from PLC programming, which is covered by our PLC, SCADA and HMI programming service.
The real work is in selecting and documenting the right variables, setting sampling rates that do not overload the controller and modelling each signal with proper context. Access is configured as read-only wherever the project allows, and the software that talks to the PLCs runs inside the OT network, publishing outwards through a controlled boundary, typically an MQTT broker (see MQTT integration). Connecting a PLC to the cloud then becomes a three-step sequence: read locally, contextualise in the plant data layer, and publish only what has a defined use, encrypted and authenticated.
How it connects to the system
Connect enables data flow to AI and Energy and supports execution that Service digitises in the business layer.
Key concepts
Other solutions
- Edge Ingestion
We capture data at the edge of the operation, where it is generated, without depending on central connectivity. We deploy edge ingestion software on plant equipment that reads signals locally, holds them through network outages and forwards them once the connection is restored.
- OT/IT Integration
We build the bridge between the operational world (OT) and the information systems world (IT): a data layer that reads plant information and delivers it to business systems, with an architecture designed not to interfere with production.
- MQTT Integration
We implement MQTT brokers and data flows to connect sensors and industrial devices at scale, with topic hierarchies designed around the plant and options such as Sparkplug B when several systems consume the same data.
Frequently asked questions
- Do you need to modify the PLC program to extract its data?
- No. Data is read through a communications channel independent of the control program, such as an embedded OPC-UA server, Modbus TCP, the S7 protocol or EtherNet/IP. The controller keeps executing its logic exactly as before, and no new code needs to be loaded nor does the machine need to stop to connect it to the data layer.
- Which PLC manufacturers do you work with?
- Any of them. We connect PLCs from Siemens, Rockwell / Allen-Bradley, Schneider, Omron, Mitsubishi, Beckhoff and other manufacturers, each through the protocol the equipment offers. For legacy controllers without a usable communications channel we evaluate hardware gateways or, as a last resort, upgrading the device, always with the cost on the table.
- Is it safe to connect PLCs to a data network or the cloud?
- Access is configured as read-only wherever the project allows: the connector queries variables but cannot write setpoints or alter the machine. The software that talks to the PLCs also runs inside the OT network and publishes outwards through a controlled boundary, so no external system ever accesses a controller directly.
- What is the difference between PLC connectivity and PLC programming?
- PLC programming writes or modifies the logic that governs the machine; PLC connectivity reads the data that logic produces from the outside, without touching the program. They are different, complementary services: if you need to change controller behaviour or develop a SCADA or HMI, the right service is PLC, SCADA and HMI programming.