PI Interface for Modbus Ethernet PLC - Read-Only 4.3

PI Interface for Modbus Ethernet PLC – Read-Only
Developer: OSIsoft, LLC

The PI Interface for Modbus Ethernet PLC – Read-Only connects the PI System to Modbus/TCP-compatible PLCs and RTUs over Ethernet to collect real-time operational data. It polls specified Modbus addresses and writes values and status to the PI Data Archive for visualization, analysis, and alerts. This read-only variant is designed strictly for data acquisition; it does not perform control actions or write to devices.

Key capabilities

• Read-only polling of Modbus/TCP devices (no writes to coils or registers)
• Support for standard Modbus objects: Coils (0x), Discrete Inputs (1x), Input Registers (3x), Holding Registers (4x)
• Flexible data mapping to PI points, including:
  
  
  • 16-bit, 32-bit, and 64-bit values assembled from multiple registers
  • Signed/unsigned integers and IEEE 754 floating-point
  • Configurable byte/word order and bit extraction for digital states
  • Optional scaling and linear conversion
• Configurable scan classes and polling rates to balance latency and load
• Multi-device support with independent connection settings per PLC/RTU
• Diagnostics and health points, with event logging and quality/status handling for communication errors
• Buffering to protect against network interruptions between the interface node and the PI Data Archive
• High availability via UniInt-based interface failover when deployed in redundant pairs
• Consistent timestamping at collection time

Architecture and requirements

• Runs as a Windows service on an interface node with IP connectivity to Modbus/TCP devices and to a PI Data Archive
• Requires a licensed PI System and the appropriate interface license; configured using standard PI administration tools
• Designed for Modbus over Ethernet/TCP; serial Modbus (RTU/ASCII) requires a different interface or the use of a serial-to-Ethernet gateway

Typical uses

• Collecting process measurements, equipment status, and alarms from PLCs/RTUs in manufacturing, power generation, water and wastewater, oil and gas, and building automation
• Centralizing operations data in the PI System for trending, analytics, notifications, and historical archiving

Limitations and notes

• Read-only: no writes, setpoint changes, or remote control are supported
• Modbus/TCP is typically unencrypted; deploy the interface within a protected network and apply standard network security controls as needed
• Device-specific register maps and scaling must be provided during configuration to ensure accurate data interpretation

For installation guidance, configuration details, and supported options, refer to the official OSIsoft documentation or contact OSIsoft/AVEVA support.

PI Interface for Modbus Ethernet PLC - Read-Only is developed by OSIsoft, LLC. The most popular versions of this product among our users are: 4.2 and 4.3.