AB 罗克韦尔1756-L71S可编程控制模块CPU中央处理模块

AB 罗克韦尔1756-L71S可编程控制模块CPU中央处理模块

AB 罗克韦尔1756-L71S可编程控制模块CPU中央处理模块

1、控制功能

逻辑控制：PLC具有与、或、非、异或和触发器等逻辑运算功能，可以代替继电器进行开关量控制。

定时控制：它为用户提供了若干个电子定时器，用户可自行设定：接通延时、关断延时和定 时脉冲等方式。

计数控制：用脉冲控制可以实现加、减计数模式，可以连接码盘进行位置检测。

顺序控制：在前道工序完成之后，就转入下一道工序，使一台PLC可作为多部步进控制器使用。

2、数据采集、存储与处理功能

数学运算功能：

基本算术：加、减、乘、除。

扩展算术：平方根、三角函数和浮点运算。

比较：大于、小于和等于。

数据处理：选择、组织、规格化、移动和先入先出。

模拟数据处理：PID、积分和滤波。

3、输入/输出接口调理功能

具有A/D、D/A转换功能，通过I/O模块完成对模拟量的控制和调节。位数和精度可以根据用 户要求选择。

具有温度测量接口，直接连接各种电阻或电偶。

4、通信、联网功能

现代PLC大多数都采用了通信、网络技术，有RS232或RS485接口，可进行远程I/O控制，多台 PLC可彼此间联网、通信，外部器件与一台或多台可编程控制器的信号处理单元之间，实现程序和数据交换，如程序转移、数据文档转移、监视和诊断。

通信接口或通信处理器按标准的硬件接口或***通信协议完成程序和数据的转移。如西门 子S7-200的Profibus现场总线口，其通信速率可以达到12Mbps。

在系统构成时，可由一台计算机与多台PLC构成“集中管理、分散控制”的分布式控制网络，以便完成较大规模的复杂控制。通常所说的SCADA系统，现场端和远程端也可以采用PLC作现场机。

AB 罗克韦尔1756-L71S可编程控制模块CPU中央处理模块

1. Control function

Logic control: PLC has and, or, not, XOR and trigger and other logic operation functions, can replace the relay for switching control.

Timing control: It provides users with a number of electronic timers, users can set: on delay, off delay and fixed time pulse and other ways.

Counting control: Adding and subtracting counting modes can be realized by pulse control, and position detection can be performed by connecting the code disk.

Sequence control: After the previous process is completed, it is transferred to the next process, so that a PLC can be used as a multi-step controller.

2, data collection, storage and processing functions

Mathematical operation function:

Basic arithmetic: addition, subtraction, multiplication and division.

Extended arithmetic: square roots, trigonometry, and floating-point operations.

Comparison: greater than, less than and equal to.

Data processing: selection, organization, normalization, movement, and first-in first-out.

Analog data processing: PID, integration and filtering.

3, input/output interface conditioning function

With A/D, D/A conversion function, through the I/O module to complete the analog control and adjustment. The number of bits and accuracy can be selected according to user requirements.

With temperature measurement interface, directly connected to various resistors or couples.

4. Communication and networking functions

Modern PLC most of the use of communication, network technology, RS232 or RS485 interface, can carry out remote I/O control, multiple PLC can network with each other, communication, external devices and one or more programmable controller signal processing unit between, to achieve program and data exchange, such as program transfer, data document transfer, monitoring and diagnosis.

The communication interface or communication processor completes the transfer of programs and data according to the standard hardware interface or the best communication protocol. Such as the Profibus fieldbus interface of Siemens S7-200, its communication rate can reach 12Mbps.

When the system is constructed, a distributed control network of "centralized management and decentralized control" can be formed by a computer and multiple PLCS to complete large-scale complex control. Generally referred to as SCADA system, the field end and remote end can also use PLC as the field machine.