8937-HN MTL开关量输入卡

 8937-HN  MTL开关量输入卡

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。

 8937-HN  MTL开关量输入卡

微机保护装置除了具有上述微机保护的优点之外，与同类产品比较具有以下特点：（1）品种齐全：微机保护装置，品种特别齐全，可以满足各种类型变配电站的各种设备的各种保护要求，这就给变配电站设计及计算机联网提供了很大方便。（2）硬件采用的芯片提高了技术上的先进性，CPU采用80C196KB，测量为14位A/D转换，模拟量输入回路多达24路，采到的数据用DSP信号处理芯片进行处理，利用高速傅氏变换，得到基波到8次的谐波，特殊的软件自动校正，确保了测量的高精度。利用双口RAM与CPU变换数据，就构成一个多CPU系统，通信采用CAN总线。具有通信速率高（可达100MHZ，一般运行在80或60MHZ）抗干扰能力强等特点。通过键盘与液晶显示单元可以方便的进行现场观察与各种保护方式与保护参数的设定。（3）硬件设计在供电电源，模拟量输入，开关量输入与输出，通信接口等采用了特殊的隔离与抗干扰措施，抗干扰能力强，除集中组屏外，可以直接安装于开关柜上。（4）软件功能丰富，除完成各种测量与保护功能外，通过与上位处理计算机配合，可以完成故障录波（1秒高速故障记录与9秒故障动态记录），谐波分析与小电流接地选线等功能。（5）可选用RS232和CAN通信方式，支持多种远动传输规约，方便与各种计算机管理系统联网。（6）采用宽温带背景240×128大屏幕LCD液晶显示器，操作方便、显示美观。（7）集成度高、体积小、重量轻，便于集中组屏安装和分散安装于开关柜上。

 8937-HN  MTL开关量输入卡

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.

8937-HN MTL Switch Input Card

In addition to the advantages of the above-mentioned microcomputer protection, microcomputer protection devices have the following characteristics compared with similar products: (1) Complete varieties: microcomputer protection devices are particularly complete, which can meet all kinds of protection requirements of various equipment in various types of power distribution stations, which provides great convenience for the design of power distribution stations and computer networking. (2) The chip used in the hardware improves the technical advancement. The CPU is 80C196KB, and the measurement is 14-bit A/D conversion. There are 24 analog input circuits. The collected data are processed by DSP signal processing chip, and the harmonics from the fundamental wave to the eighth order are obtained by using high-speed Fourier transform. Special software automatically corrects them, ensuring the high accuracy of the measurement. By using dual-port RAM and CPU to convert data, a multi-CPU system is formed, and CAN bus is used for communication. It has the characteristics of high communication speed (up to 100MHZ, generally operating at 80 or 60MHZ) and strong anti-interference ability. Through the keyboard and liquid crystal display unit, it is convenient to observe the scene and set various protection methods and protection parameters. (3) The hardware design adopts special isolation and anti-interference measures in power supply, analog input, switch input and output, communication interface, etc., which has strong anti-interference ability and can be directly installed on the switch cabinet in addition to centralized screen assembly. (4) The software is rich in functions. In addition to various measurement and protection functions, it can complete fault wave recording (1 second high-speed fault recording and 9 seconds fault dynamic recording), harmonic analysis and small current grounding line selection by cooperating with the upper processing computer. (5) RS232 and CAN communication modes can be selected to support various telecontrol transmission protocols and facilitate networking with various computer management systems. (6) It adopts 240×128 large-screen LCD with wide temperate background, which is convenient to operate and beautiful to display. (7) High integration, small volume and light weight, which is convenient for centralized panel installation and decentralized installation on switchgear.