EMERSON VE3008 12P3439X012 KJ2003X1-BB1 模块

EMERSON VE3008 12P3439X012 KJ2003X1-BB1 模块

EMERSON VE3008 12P3439X012 KJ2003X1-BB1 模块

谈到 PLC向外部设备、仪表发送信号，有一种情况经常遇到:要求PLC的输出即能给显示仪表，又能传送给变频器一类的设备。欲彻底解决干扰问题，推荐使用隔离式信号分配器。这种隔离器即实现 PLC输出信号与外设隔离，同时实现外设之间隔离。有时现场仪表在配套时，由于协调不利，产生了如下情况，接收信号设备(例如接收 420mA)接口连接为两线制方式也即接收口为一个24V 电源与一个250Q相串联接口两根线:一个为24V正极，一个为250Q一端，适于连接现场两线制变送器。假如现场设备为四线制变送器，输出4-20mA。这样进行直接连接将造成电源冲突。解决方法是采用隔离器将现场来的4-20mA接收并隔离，在隔离器的输出部份接入一个标准的两线制变送器，以应对接收设备的接口。

工业控制实现自动化与PLC的加入有非常大的关系，PLC在工业生产线中主要功能为：开环控制、模拟量闭环、数字量控制等，这在很多场景下可以取代传统的继电接触器控制系统，让工业控制系统实现自动化生产。此外，PLC除了控制外，还可以实现采集现场数据的功能，并且可以对数据进行统计和记录。

由于PLC大多数都使用了单片微型计算机，所以集成度非常高，这也增加了系统的可靠性。PLC的优势在于输入和输出功能模块兼具，可以针对现场不同的信号，采用与之匹配的模板与对应的设备相连接并采取控制。除此之外，PLC还具备变成容易、组态灵活、安装方便、运行速度快。

当前在PLC领域中，企业基本上都属于欧美日三个地区。欧洲以西门子、施耐德为主，美国市场以罗克韦尔、通用为主，而日本市场则以欧姆龙、三菱和松下。而国产品牌在PLC方面近些年也发展迅速，和利时、信捷电气、南大傲拓、汇川技术、英威腾等自主品牌也在致力研发PLC，不过仍是以中小型PLC为主，大型的PLC系统仍被国际品牌占据，国内自主品牌仍有很大的进步空间。

EMERSON VE3008 12P3439X012 KJ2003X1-BB1 模块

When it comes to PLC sending signals to external equipment and instruments, there is a situation that is often encountered: the output of PLC is required to be sent to both display instruments and devices such as frequency converters. To completely solve the interference problem, it is recommended to use an isolated signal distributor. This kind of isolator not only realizes the isolation of PLC output signal from peripherals, but also realizes the isolation between peripherals. Sometimes, when the field instruments are matched, due to poor coordination, the following situations occur: the interface of the signal receiving equipment (for example, receiving 420mA) is connected in two-wire mode, that is, the receiving port is connected with two wires of a 24V power supply and a 250Q serial interface: one is a 24V positive electrode and the other is a 250Q end, which is suitable for connecting the field two-wire transmitter. If the field equipment is a four-wire transmitter, the output is 4-20mA. Direct connection in this way will cause power conflict. The solution is to use an isolator to receive and isolate the 4-20mA from the site, and connect a standard two-wire transmitter to the output part of the isolator to cope with the interface of the receiving equipment.

The automation of industrial control has a great relationship with the addition of PLC. The main functions of PLC in industrial production line are: open-loop control, analog closed-loop control, digital control, etc. This can replace the traditional relay contactor control system in many scenarios and make the industrial control system realize automatic production. In addition, PLC can not only control, but also realize the function of collecting field data, and can count and record the data.

EMERSON VE3008 12P3439X012 KJ2003X1-BB1 模块

Because most PLCs use single-chip microcomputers, the integration is very high, which also increases the reliability of the system. The advantage of PLC is that it has both input and output function modules, and it can connect with the corresponding equipment and take control according to different signals in the field by matching templates. In addition, PLC also has the advantages of easy conversion, flexible configuration, convenient installation and fast operation.

At present, in the field of PLC, enterprises basically belong to Europe, America and Japan. Europe is dominated by Siemens and Schneider, while the American market is dominated by Rockwell and General Motors, while the Japanese market is dominated by Omron, Mitsubishi and Panasonic. Domestic brands have also developed rapidly in PLC in recent years, and independent brands such as Hollysys, Xinjie Electric, Nantah Alto, Huichuan Technology and Invigorate are also working hard to develop PLC, but they are still mainly small and medium-sized PLCs, and large-scale PLC systems are still occupied by international brands, so there is still much room for improvement for domestic independent brands.