目前很多现代化的工业应用需要更多的功能要求，如网络连接、设备互用、企业数据集成等，这些都远远超过了传统的、基于离散逻辑控制的PLC所能提供的功能，想要基于PLC的系统实现这些功能，必须用单独的处理器、网关获转换器，运行于独立的PC软件中间件以及企业系统级的专用软件进行系统集成。
PC-Based在自动化应用初期被PLC阵营高度质疑，至今市场上仍有相关疑虑，主要问题有稳定性、可靠性和程式设计环境不稳定三点，因此也有工程师将PLC配合PC使用，不过这在系统整合上比较麻烦。
为了解决PLC和PC-Based的整合问题，美国研究机构ARC提出了PAC架构的控制器（可编程自动化控制器），PAC融合了PLC和PC-Based两种技术，在PC层面，会大量应用嵌入式技术，拥有使用软体来定义硬体的能力就是其一。
拥护者认为，PAC的价值在于所有部件均按照软件和硬件集成最灵活、最方便、成本为出发点，从而使得用户设备的生命周期成本较低，资产的投资回报率提高，资产所有者总成本下降。
当然，也有观点认为，PAC仍属于PC-Based产品，只是换了另外一种包装。但就市场整体面来看，PAC的确已经逐渐成形，包括西门子在内的大厂，均已纷纷推出产品，国内像研华也推出了全新一代的PAC控制器APAX-5000系列。
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