07KR51 1SBP260011R1001 工业自动化 控制模块 DCS PLC系统

07KR51 1SBP260011R1001 工业自动化 控制模块 DCS PLC系统

CPU 是 PLC 的实际“大脑”，使其成为计算机。即使是小型的非模块化 PLC 也包含一个 CPU。输入信号来自 I/O 卡，逻辑程序根据信号做出决策。如果需要，CPU 然后命令输出随着信号和条件的变化而打开和关闭。

程序可能包括高 级功能，例如数学运算、计时、计数和通过现代网络协议共享信息。对于较旧的中继系统，其中许多操作即使不是不可能，也是极其困难的。

输入/输出卡

传感器、按钮、开关、继电器、螺线管甚至网络设备与连接到 I/O 卡上的螺丝端子的 I/O 信号共享信息。可以根据每台机器和设​​施的需要选择这些卡。在一些小型 PLC中，I/O 端子不是模块化卡，而是方便地安装在 PLC 的侧面。

由于 I/O 设备结构种类繁多，分立和模拟模块的种类繁多，模拟模型的术语有“源”与“灌”，“电压”与“电流” 。

编程设备和人机界面

PLC 本身之外有两个非常重要的组件：编程设备和人机界面 (HMI)。编程设备可以是来自同一制造商的台式计算机、膝上型计算机或手持式仪器。一些小型 PLC 甚至在前面有按钮，可以在不需要计算机的情况下对非常基本的逻辑操作进行编程。

The CPU is the actual "brain" of the PLC, making it a computer. Even small non-modular PLCS contain a CPU. The input signal comes from the I/O card, and the logic program makes decisions based on the signal. If needed, the CPU then commands the output to turn on and off as signals and conditions change.

Programs may include advanced functions such as mathematical operations, timing, counting, and sharing information over modern network protocols. Many of these operations are extremely difficult, if not impossible, for older relay systems.

Input/output card

Sensors, buttons, switches, relays, solenos, and even network devices share information with the I/O signals connected to the screw terminals on the I/O card. These cards can be selected according to the needs of each machine and device. In some small PLCS, the I/O terminals are not modular cards, but are conveniently mounted on the side of the PLC.

Due to the wide variety of I/O device structures and the wide variety of discrete and analog modules, the terms of the simulation model are "source" and "perfusion", "voltage" and "current".

Programming devices and human-machine interfaces

There are two very important components outside the PLC itself: the programming device and the human machine interface (HMI). The programming device can be a desktop computer, laptop, or handheld instrument from the same manufacturer. Some small PLCS even have buttons on the front that allow very basic logic operations to be programmed without the need for a computer.