To alleviate duplication efforts in developing device-specific protocols, eliminate inconsistencies between devices, provide support for hardware feature changes, and avoid access conflicts in industrial control systems, the OPC Foundation defined a set of standard interfaces that allow any client to access any OPC-compatible device. Most suppliers of industrial data acquisition and control devices, such as Programmable Logic Controllers (PLCs) and Programmable Automation Controllers (PACs), are designed to work with the OPC Foundation standard.