2351模块备件产品重量

对用户存储容量只能作大略的预算。在仅对开关量进行操控的体系中，能够用输入总点数乘 10 字/ 点＋输出总点数乘 5 字 / 点来预算；计数器 / 定时器按（ 3 ～ 5 ）字 / 个预算；有运算处理时按（ 5 ～ 10 ）字 / 量预算；在有模拟量输入 / 输出的体系中，能够按每输入 / （或输出）一路模拟量约需（ 80 ～ 100 ）字左右的存储容量来预算；有通讯处理时按每个接口 200 字以上的数量大略预算。终，一般按预算容量的 50 ～ 100 ％留有裕量。对缺乏阅历的规划者，挑选容量时留有裕量要大些。
（ 3 ）对 I/O 响应时刻的挑选
PLC 的 I/O 响应时刻包括输入电路推迟、输出电路推迟和扫描作业办法引起的时刻推迟（一般在 2 ～ 3 个扫描周期）等。对开关量操控的体系， PLC 和 I/O 响应时刻一般都能满意实践工程的要求，可不必考虑 I/O 响应问题。但对模拟量操控的体系、特别是闭环体系就要考虑这个问题。

The user storage capacity can only be roughly budgeted. In the system that only controls the switching value, the total number of input points multiplied by 10 words / point + the total number of output points multiplied by 5 words / point can be used to budget; The counter / timer is budgeted by (3 ~ 5) words / piece; Budget according to (5 ~ 10) words / quantity when there is calculation processing; In the system with analog input / output, it can be budgeted according to the storage capacity of about (80 ~ 100) words for each input / (or output) analog; When there is communication processing, the rough budget is based on the quantity of more than 200 words per interface. Finally, there is usually a margin of 50 ~ 100% of the budgeted capacity. For inexperienced planners, it is better to leave more margin when selecting capacity.
(3) Selection of i/o response time
The i/o response time of PLC includes input circuit delay, output circuit delay and time delay caused by scanning operation method (generally in 2 ~ 3 scanning cycles), etc. For the switching value control system, the PLC and i/o response time can generally meet the requirements of practical engineering, so it is unnecessary to consider the i/o response problem. However, this problem should be considered for the analog control system, especially the closed-loop system.