Edge Gateway

An edge gateway is a physical device installed in the plant that acts as a bridge between your field equipment and the Rela AI cloud platform. It collects data from sensors, PLCs, and industrial equipment using local protocols (Modbus, OPC UA, MQTT) and forwards it to the platform. If the internet connection is lost, it stores the data locally — up to 72 hours — and synchronizes automatically when connectivity returns.

What is it for?

Many industrial sensors and PLCs cannot connect to the internet directly. They use proprietary industrial protocols (Modbus TCP, OPC UA) that require a local device to translate and forward the data. The edge gateway is that device: it sits in the local network, reads from industrial equipment, and bridges the gap to the cloud.

Edge gateways are essential for:

• Connecting PLCs, SCADA systems, and Modbus devices that cannot speak directly to cloud APIs
• Plants with intermittent internet connectivity where data cannot be lost during outages
• High-frequency sensor data that needs local buffering before transmission
• Sites with strict network security where cloud connections must be controlled

How does it work?

After installation and registration, the gateway:

1. Connects to the configured sensors and PLCs using the specified protocol and address
2. Reads data at the configured interval (e.g., every 30 seconds)
3. Forwards readings to Rela AI in the cloud
4. If internet connectivity is lost, stores readings locally
5. When connectivity returns, synchronizes all stored data in chronological order
6. Sends a heartbeat signal every 60 seconds so the platform knows it is functioning

How to use it?

Register a new gateway

After physically installing the gateway device at the plant:

1. Go to Integrations > Edge Gateways in the sidebar.
2. Click Register Gateway.
3. Enter the gateway information:
   • Name: descriptive identifier (e.g., "North Plant Gateway — Building A")
   • Model: hardware model of the device
   • Location: building, floor, and zone where it is installed
   • Protocols: which industrial protocols this gateway uses (Modbus, OPC UA, MQTT)
4. Save. The system generates a unique authentication token — configure this token in the physical device.

Monitor your gateway fleet

The fleet view shows all registered gateways with their current status:

Assign data sources to a gateway

Once the gateway is registered and online, configure which sensors and PLCs it should read:

1. Select the gateway.
2. Click Add Data Source.
3. Configure each source:
   • Source name: how this sensor will appear in the platform
   • Protocol: Modbus, OPC UA, or MQTT
   • Address or topic: the specific register address (Modbus) or topic path (MQTT) to read
   • Reading interval: how often to read the value (e.g., every 30 seconds)

A single gateway can connect up to 500 data sources depending on your plan.

Understand the offline buffer

When the gateway loses internet connectivity:

• It continues reading from all connected sensors and PLCs normally
• All readings are stored locally in compressed format
• When connectivity returns, stored data is sent to the platform in chronological order
• The platform automatically discards any duplicate readings

The local buffer holds up to 72 hours of data. If the outage lasts longer than 72 hours, the oldest data is lost. The fleet dashboard shows how much buffered data each gateway has pending synchronization.

Update gateway firmware

When a firmware update is available:

1. Select the gateway.
2. Click Update Firmware.
3. Choose the target version and schedule the update for a low-traffic window (e.g., 2 AM).
4. Enable automatic rollback if something goes wrong.

The gateway will download and install the update at the scheduled time. If the gateway does not confirm successful startup within 10 minutes after the update, and automatic rollback is enabled, it reverts to the previous version automatically.

Key benefits

• Connects any industrial sensor or PLC regardless of its network capabilities
• Local data buffer prevents data loss during internet outages (up to 72 hours)
• Automatic synchronization when connectivity returns — no manual intervention
• Real-time fleet monitoring with health status for every gateway
• Supports Modbus, OPC UA, and MQTT protocols in the same device
• Scheduled firmware updates with automatic rollback protection

Common use cases

Scenario 1: Connecting PLCs in a plant with intermittent connectivity A remote mining plant has unreliable satellite internet that drops for hours at a time. An edge gateway is installed in the electrical room, connected to the 8 main PLCs via OPC UA. During internet outages, the gateway buffers sensor readings locally. When connectivity returns, all data is synchronized to Rela AI in the correct chronological order. The condition monitoring system has complete historical data with no gaps.

Scenario 2: Large facility with multiple zones A large petrochemical complex has 3 production areas, each with separate network segments. Three edge gateways are installed — one per area. Each gateway connects to the sensors and PLCs in its zone using Modbus. The fleet dashboard gives the infrastructure team visibility into all three gateways' health simultaneously. When the Area B gateway goes to "degraded" status, the team investigates before it goes fully offline.

Scenario 3: High-frequency vibration monitoring Vibration sensors on critical rotating equipment send readings every 5 seconds. Direct cloud transmission at that frequency would overwhelm the connection. The edge gateway collects all readings locally and forwards aggregated data every 30 seconds to the platform — preserving the detail in the buffer while reducing network traffic by 83%.