PyPLC, A VERSATILE PLC-TO-PC PYTHON INTERFACE

The PyPLC Tango Device Server provides a developerfriendly dynamic interface to any Modbus-based control device. Raw data structures from PLC are obtained efficiently and converted into highly customized attributes using the python programming language. The device server allows to add or modify attributes dynamically using single-line python statements. The compact python dialect used is enhanced with Modbus commands and methods to prototype, simulate and implement complex behaviours. As a generic device, PyPLC has been versatile enough to interact with PLC systems used in ALBA Accelerators as well as to our Beamlines SCADA (Sardana). This article describes the mechanisms used to enable this versatility and how the dynamic attribute syntax allowed to speed up the transition from PLC to user interfaces.