Data Collection & PI Interfaces

PI Interface Architecture

PI Interfaces are the data collection agents that bridge industrial control systems to the PI Data Archive. Each interface is a Windows service that runs on an Interface Node — a dedicated server positioned close to the data source.

Interface Node Design

The Interface Node pattern separates data collection from the PI Server:

DCS / SCADA / PLC
      │
      ▼
Interface Node (Windows Server)
├── PI OPC DA Interface
├── PI Buffering Agent (PIBUFSS)
└── PI Interface Manager
      │
      ▼ (TCP/IP - PI Native Protocol)
PI Data Archive Server

Key benefits of this architecture:

• Isolates PI Server from direct field network exposure
• Enables buffering during network outages
• Allows multiple interfaces per node
• Reduces load on the PI Server

OPC DA Interface Configuration

OPC DA (Data Access) is the most common interface type for connecting to DCS and SCADA systems.

Configuration Steps

1. Install PI OPC DA Interface on the Interface Node

2. Configure the OPC Server connection in PI ICU (Interface Configuration Utility)

3. Define PI points with correct tag attributes

4. Set scan classes based on required data frequency

5. Enable PIBUFSS for data buffering

Critical Tag Attributes for OPC DA

PI Buffering Agent (PIBUFSS)

PIBUFSS is critical for data reliability. It stores data locally when the PI Server is unreachable and forwards it when connectivity is restored.

PIBUFSS Configuration

# pibufss.ini key settings
[PIBUFSS]
PIServer=PISERVER01
BufferPath=C:\PI\buf\
MaxBufferSize=1024  ; MB
SendRate=1000       ; events/second

OPC UA Interface

OPC UA (Unified Architecture) is the modern, secure successor to OPC DA:

• Security: Built-in certificate-based authentication
• Platform independent: Works on Linux, embedded systems
• Information model: Hierarchical node structure
• Transport: TCP binary or HTTPS