1756-L61B 备份控制器可以自动接管控制任务，保证系统的连续运行

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1756-L61B 备份控制器可以自动接管控制任务，保证系统的连续运行

1756-L61B 可编程自动化控制器（PAC）与可编程逻辑控制器（PLC）有以下几个区别：
1. 名称由来：在第一代PLC时期，PLC主要用于替代硬接线继电器和气动计时器，那时被称为可编程控制器，简称PC。但是很快，在1980年代初期，PC这个名称被个人计算机霸占了，于是就经常使用PLC这个词了。PAC这个名称则出现于大概15年前，它的出现也许是为了将功能最强的PLC从其它稍逊一筹的弟兄们中区分开来。
2. 定义：很多生产制造商在区分PAC和PLC方面存在困难，原因在于两者之间有很多重要但是共同的特性。这些共同的特性和功能包括高速CPU，提供快速扫描；基于标签名的功能；大容量板载存储；文档存储在控制器中；任务管理程序组织；多种内置网络协议；数据采集。
3. 功能：相较于千禧年之初的大多数PC机，最新的PLC和PAC处理器芯片的处理频率要高得多。这种技术进步适用于各个等级的控制器。在考虑CPU的性能和费用方面，这更多的是生产制造商的一种偏好。在很多机器控制领域和其它需要非常快的执行速度的场合，都需要这些高速CPU。

1756-L61B PLC的高可靠性主要体现在以下几个方面：

硬件设计：PLC的硬件设计采用大规模集成电路技术，具有很高的可靠性。同时，PLC的电源、输入输出端口等关键部件都采用了抗干扰技术，进一步提高了其抗干扰能力和可靠性。
冗余设计：一些高端的PLC采用了冗余设计，即主控制器和备份控制器同时工作，当主控制器出现故障时，备份控制器可以自动接管控制任务，保证系统的连续运行。
自诊断功能：PLC具有自诊断功能，能够实时检测自身的硬件和软件状态，一旦发现异常或故障，可以立即进行报警或故障排除，保证系统的稳定运行。
可靠性设计：PLC的软件系统采用了循环扫描、故障检测、故障处理等可靠性设计技术，能够减少系统故障的发生概率。
耐环境性：PLC的设计考虑了工业环境下的恶劣条件，如高温、低温、潮湿、振动等，能够在这些环境下稳定运行。
维护方便：PLC的模块化设计使得其维护变得非常方便，一旦某个模块出现故障，可以迅速更换故障模块，保证系统的连续运行。
综上所述，PLC具有高可靠性，其硬件设计、冗余设计、自诊断功能、可靠性设计、耐环境性和维护方便等特点都使得其在工业自动化控制领域得到了广泛应用。

1756-L61B 备份控制器可以自动接管控制任务，保证系统的连续运行

1756-L61B Programmable Automation controller (PAC) and programmable logic controller (PLC) has the following differences:
1. Name origin: In the first generation of PLC period, PLC is mainly used to replace hard-wired relays and pneumatic timers, then called programmable controller, referred to as PC. But soon, in the early 1980s, the name PC was taken over by personal computers, and the word PLC was often used. The name PAC appeared about 15 years ago, perhaps to distinguish the most powerful PLCS from their less powerful brethren.
2. Definition: Many manufacturers have difficulty distinguishing between a PAC and a PLC because there are many important but common characteristics between the two. These common features and functions include a high-speed CPU that provides fast scanning; Function based on tag name; Large capacity onboard storage; Documents are stored in the controller; Task management program organization; Multiple built-in network protocols; Data acquisition.
3. Features: The latest PLC and PAC processor chips have a much higher processing frequency than most PCS at the beginning of the millennium. This technological advancement is applicable to all levels of controllers. In terms of CPU performance and expense, this is more of a preference of the production manufacturer. These high-speed cpus are needed in many areas of machine control and other situations where very fast execution speeds are required.

The high reliability of 1756-L61B PLC is mainly reflected in the following aspects:

Hardware design: The hardware design of PLC adopts large-scale integrated circuit technology, which has high reliability. At the same time, the PLC power supply, input and output ports and other key components have adopted anti-interference technology, further improving its anti-interference ability and reliability.
Redundant design: Some high-end PLC adopts redundant design, that is, the master controller and backup controller work at the same time, when the master controller fails, the backup controller can automatically take over the control task to ensure the continuous operation of the system.
Self-diagnosis function: PLC has a self-diagnosis function, can detect its own hardware and software status in real time, once found abnormal or fault, can immediately alarm or troubleshooting, to ensure the stable operation of the system.
Reliability design: PLC software system adopts reliability design technology such as cyclic scanning, fault detection and fault processing, which can reduce the probability of system failure.
Environmental resistance: The design of the PLC takes into account the harsh conditions in the industrial environment, such as high temperature, low temperature, humidity, vibration, etc., and can operate stably in these environments.
Easy maintenance: The modular design of PLC makes its maintenance very convenient, once a module fails, you can quickly replace the faulty module to ensure the continuous operation of the system.
In summary, PLC has high reliability, its hardware design, redundancy design, self-diagnosis function, reliability design, environmental resistance and easy maintenance and other characteristics make it widely used in the field of industrial automation control.