Protocols

A protocol defines how Koios communicates with an external device or data source. When you create a device, you choose a protocol — this determines the connection settings you'll need to provide and the types of tags you can create.

Supported Protocols

Protocol Details

OPC-UA

OPC Unified Architecture is the modern standard for industrial data exchange. It provides a platform-independent, service-oriented architecture for communicating with PLCs, SCADA systems, historians, and other industrial equipment.

Koios connects as an OPC-UA client and supports:

• Server discovery — browse your network for available OPC-UA servers and endpoints
• Security modes — None, Sign, or Sign & Encrypt
• Security policies — Basic128Rsa15, Basic256, Basic256Sha256
• Authentication — Anonymous or Username/Password
• Node browsing — explore the server's address space to find and select tags

Modbus TCP

Modbus TCP is a widely-used protocol for communicating with sensors, meters, and simple PLCs over Ethernet. It uses a register-based addressing model where data points are identified by register type and address number.

EtherNet/IP

EtherNet/IP (Ethernet Industrial Protocol) uses the Common Industrial Protocol (CIP) to communicate with industrial devices over standard Ethernet. Koios supports two device types under this protocol:

• Logix Controller — connects to Allen-Bradley ControlLogix and CompactLogix controllers using tag-based addressing. Includes a tag browser for exploring the controller's tag database.
• Generic CIP — connects to any CIP-compliant device (variable frequency drives, I/O modules, non-Allen-Bradley equipment) using assembly-based addressing. Supports EDS file upload for structured browsing of device data.

SOAP

The SOAP (Simple Object Access Protocol) implementation in Koios is designed for RDM (Resource Data Manager) controllers. RDM devices expose a SOAP-based API for reading and writing HVAC parameters.

REST

The REST protocol connects to HTTP-based APIs, such as CAREL BOSS building management systems. Koios sends HTTP requests to the configured endpoint and parses the response to extract tag values.

Microsoft SQL

Microsoft SQL devices allow Koios to query data from SQL Server databases using ODBC. Each tag on an SQL device executes a SQL query on every scan cycle and stores the result as a live value. This is useful for integrating data from business systems, energy management platforms, or external historians.

Certificates

Some OPC-UA servers require certificate-based trust in addition to (or instead of) username/password authentication. See OPC-UA Certificates for details on managing certificates in Koios.