Introduction

The PI Interface for Modbus Ethernet PLC interface can be run on either a PI 3 server node or a PI interface node that communicates to a Data Archive. Only Modbus communication with an ethernet device is supported.

The interface is designed to read data from a PLC on a periodic or event basis, and to send output data (commands to the PLC) on an event basis. The ModbusE interface attempts to optimize scanning performance by grouping input tags with the same scan rate, PLC destination node, and function code.

Throughout this manual there are references to messages written by the interface which is the PIPC.log file. This interface has been built against UniInt version (4.7.3) which now writes all messages to the local PI message log.

Any references to PIPC.log should now refer to the local PI message log. See the UniInt Interface Message Logging document in the %PIHOME%\Interfaces\UniInt directory for details on how to access these messages.

Note: The value of PIHOME variable for the 32-bit interface depends on whether the interface is being installed on a 32-bit operating system (C:\Program Files\PIPC) or a 64-bit operating system (C:\Program Files (x86)\PIPC).

The value of PIHOME64 variable for a 64-bit interface is C:\Program Files\PIPC on the 64-bit operating system. PIHOME will be used to represent the value for either PIHOME or PIHOME64. The value of PIHOME is the directory which is the common location for PI client applications.