HIMA(黑马) F3236中央处理器模块卡件 PLC/DCS备件

HIMA(黑马) F3236中央处理器模块卡件 PLC/DCS备件

HIMA(黑马) F3236中央处理器模块卡件 PLC/DCS备件

I/O点数估算时应考虑适当的余量，通常根据统计的输入输出点数，再增加10%~20%的可扩展余量后，作为输入输出点数估算数据。实际订货时，还需根据制造厂商可编程逻辑控制器的产品特点，对输入输出点数进行圆整。

存储器容量是可编程序控制器本身能提供的硬件存储单元大小，程序容量是存储器中用户应用项目使用的存储单元的大小，因此程序容量小于存储器容量。设计阶段，由于用户应用程序还未编制，因此，程序容量在设计阶段是未知的，需在程序调试之后才知道。为了设计选型时能对程序容量有一定估算，通常采用存储器容量的估算来替代。

存储器内存容量的估算没有固定的公式，许多文献资料中给出了不同公式，大体上都是按数字量I/O点数的10~15倍，加上模拟I/O点数的100倍，以此数为内存的总字数(16位为一个字)，另外再按此数的25%考虑余量。

在制造工业中存在大量的开关量为主的开环的顺序控制，它按照逻辑条件进行顺序动作号按照时序动作;另外还有与顺序、时序无关的按照逻辑关系进行连锁保护动作的控制;以及大量的开关量、脉冲量、计时、计数器、模拟量的越限报警等状态量为主的-离散量的数据采集监视。

由于这些控制和监视的要求，使PLC发展成了取代继电器线路和进行顺序控制为主的产品。PLC厂家在原来CPU模板上提逐渐增加了各种通讯接口，现场总线技术及以太网技术也同步发展，使PLC的应用范围越来越广泛。

 PLC具有稳定可靠、价格便宜、功能齐全、应用灵活方便、操作维护方便的优点，这是它能持久的占有市场的根本原因。

HIMA(黑马) F3236中央处理器模块卡件 PLC/DCS备件

I/O point estimation should consider the appropriate margin, usually according to the statistical input and output points, and then increase the expandable margin of 10% to 20%, as the input and output point estimation data. When actually ordering, it is also necessary to round out the input and output points according to the product characteristics of the manufacturer's programmable logic controller.

The memory capacity is the size of the hardware storage unit that can be provided by the programmable controller itself, and the program capacity is the size of the storage unit used by the user application project in the memory, so the program capacity is less than the memory capacity. In the design phase, because the user application has not yet been written, the program capacity is unknown in the design phase and needs to be known after the program debugging. In order to have a certain estimation of program capacity during the design and selection, the estimation of memory capacity is usually used instead.

There is no fixed formula for the estimation of memory memory capacity, and different formulas are given in many literatures, which are generally 10 to 15 times the number of digital I/O points, plus 100 times the analog I/O points, and this number is the total number of words in memory (16 bits for a word), and then consider the margin according to 25% of this number.

In the manufacturing industry, there are a large number of open-loop sequential control based on switching quantity, which carries out sequential action according to logical conditions. In addition, there is the control of chain protection action which has nothing to do with sequence and timing according to logical relationship; And a large number of switching quantity, pulse quantity, timing, counter, analog quantity alarm and other state quantity - discrete quantity data acquisition monitoring.

Due to these control and monitoring requirements, the PLC has been developed to replace relay lines and sequential control products. PLC manufacturers have gradually increased a variety of communication interfaces on the original CPU template, and fieldbus technology and Ethernet technology have also developed simultaneously, making the application range of PLC more and more extensive.

PLC has the advantages of stable and reliable, cheap price, complete functions, flexible and convenient application, easy operation and maintenance, which is the fundamental reason why it can occupy the market for a long time.