1794-ASB 工业自动化 控制模块 DCS PLC系统

1794-ASB 工业自动化 控制模块 DCS PLC系统

1794-ASB 工业自动化 控制模块 DCS PLC系统

可编程逻辑控制器或 PLC 在当今的各种流程和制造行业中无处不在。PLC 最初旨在取代机电继电器系统，以便为修改控制系统的操作提供更简单的解决方案。无需重新连接大量继电器，只需从 PC 或编程设备快速下载，即可在几秒钟内更改控制逻辑。

PLC 是一种工业级数字计算机，旨在执行控制功能，尤其适用于工业应用。

今天的大多数 PLC 都是模块化的，允许用户添加各种功能，包括离散和模拟输入和输出、PID 控制、位置控制、电机控制、串行通信和高速网络。与继电器组等较旧的技术相比，PLC 更易于故障排除和维护、更可靠、更具成本效益且用途更广泛。

Modicon 是“模块化数字控制器”的缩写，它既是1968 年发明的第一个 PLC 产品的名称，也是发明它的品牌，尽管现在归施耐德电气所有。

虽然它可能看起来不像典型的家用计算机，但 PLC 的核心与大多数人在日常生活中使用的计算机和智能设备中所见的技术完全相同。

基本组件

PLC由几个基本部分组成。它们可能看起来与各个制造商略有不同，但每个组件的用途和范围是相同的。其中包括电源、中央处理单元 (CPU)、输入/输出卡以及放置输入/输出 (I/O) 卡的背板或机架。

如图 2 所示，背板在所有独立组件之间建立了电气连接，从而为 PLC 提供了模块化设计。这种电连接包括电源和通信信号。许多 PLC 制造商在背板上使用专有通信协议，以便 I/O 可以安全地与 CPU 通信。

电源

根据应用和安装环境，电源可接受 120VAC 或 24VDC。如上所述，此电压通过背板为 CPU 和 I/O 模块提供电源，这些模块以“卡”的形式出现。这些卡可以从它们在载体中的插槽中快速添加或移除。

需要注意的是，CPU 的电源并不为传感器和线圈等现场设备供电。此电源连接必须单独与卡建立。

1794-ASB 工业自动化 控制模块 DCS PLC系统

Programmable logic controllers, or PLCS, are ubiquitous in a variety of processes and manufacturing industries today. PLCS were originally designed to replace electromechanical relay systems in order to provide a simpler solution for modifying the operation of control systems. Instead of reconnecting a large number of relays, you can quickly download them from a PC or programming device and change the control logic in seconds.

A PLC is an industrial-grade digital computer designed to perform control functions and is particularly suitable for industrial applications.

Most PLCS today are modular, allowing users to add a variety of functions, including discrete and analog inputs and outputs, PID control, position control, motor control, serial communication, and high-speed networking. PLCS are easier to troubleshoot and maintain, more reliable, more cost-effective, and more versatile than older technologies such as relay groups.

Modicon, short for "modular digital controller," is both the name of the first PLC product invented in 1968 and the brand that invented it, although it is now owned by Schneider Electric.

While it may not look like a typical home computer, the core of a PLC is exactly the same technology that most people see in the computers and smart devices they use in their daily lives.

Basic component

A PLC consists of several basic parts. They may look slightly different from individual manufacturers, but the purpose and scope of each component is the same. These include the power supply, the central processing unit (CPU), the input/output card, and the backplane or rack that houses the input/output (I/O) card.

As shown in Figure 2, the backplane establishes electrical connections between all the individual components, thus providing a modular design for the PLC. This electrical connection includes a power supply and a communication signal. Many PLC manufacturers use proprietary communication protocols on the backplane so that I/O can securely communicate with the CPU.

Power source

Depending on the application and installation environment, the power supply can accept either 120VAC or 24VDC. As mentioned above, this voltage supplies power to the CPU and I/O modules through the backplane, which come in the form of "cards." These cards can be quickly added or removed from their slots in the carrier.

It should be noted that the CPU's power supply does not power field devices such as sensors and coils. This power connection must be established separately from the card.