K9203 996920302 HIMA 控制器处理器模块

K9203 996920302  HIMA 控制器处理器模块

数据缓冲:由于I/O设备的速率较低而CPU和内存的速率却很高，故在控制器中必须设置一缓冲器。在输出时，用此缓冲器暂存由主机高速传来的数据，然后才以I/0设备所具有的速率将缓冲器中的数据传送给I/0设备;在输入时，缓冲器则用于暂存从I/O设备送来的数据，待接收到一批数据后，再将缓冲器中的数据高速地传送给主机。差错控制:设备控制器还兼管对由I/O设备传送来的数据进行差错检测。若发现传送中出现了错误，通常是将差错检测码置位，并向CPU报告，于是CPU将本次传送来的数据作废，并重新进行一次传送。这样便可保证数据输入的正确性。 数据交换:这是指实现CPU与控制器之间、控制器与设备之间的数据交换。对于前者,是通过数据总线，由CPU并行地把数据写入控制器，或从控制器中并行地读出数据;对于后者，是设备将数据输入到控制器，或从控制器传送给设备。为此，在控制器中须设置数据寄存器。在用户程序执行阶段，PLC总是按由 上而下的顺序依次地扫描用户程序(梯形图)。在扫描每一条梯形图时， 又总是先扫描梯形图左边的由各触点构成的控制线路,并按先左后右、先上后下的顺序对由触点构成的控制线路进行逻辑运算,然后根据逻辑运算的结果，刷新该逻辑线圈在系统RAM存储区中对应位的状态;或者刷新该输出线圈在I/O映象区中对应位的状态;或者确定是否要执行该梯形图所规定的特殊功能指令。即，在用户程序执行过程中，只有输入点在I/O映象区内的状态和数据不会发生变化，而其他输出点和软设备在I/O映象区或系统RA存储区内的状态和数据都有可能发生变化，而且排在上面的梯形图，其程序执行结果会对排在下面的凡是用到这些线圈或数据的梯形图起作用;相反,排在下面的梯形图，其被刷新的逻辑线圈的状态或数据只能到下一个扫描周期才能对排在其上面的程序起作用。

K9203 996920302  HIMA 控制器处理器模块

Data Buffer: Because the speed of I/O device is low and the speed of CPU and memory is high, a buffer must be set in the controller. When outputting, this buffer is used to temporarily store the data transmitted by the host at high speed, and then the data in the buffer is transmitted to the I/O device at the rate that the I/O device has; At the time of input, the buffer is used to temporarily store the data sent from I/O equipment, and then transmit the data in the buffer to the host at high speed after receiving a batch of data. Error control: the device controller is also responsible for error detection of data transmitted by I/O devices. If an error is found in the transmission, the error detection code is usually set and reported to the CPU, so the CPU invalidates the data transmitted this time and transmits it again. This can ensure the correctness of data input. Data exchange: this refers to the realization of data exchange between CPU and controller, and between controller and equipment. For the former, the CPU writes data into the controller in parallel or reads data from the controller in parallel through the data bus; For the latter, it is the device that inputs data to the controller or transmits data from the controller to the device. Therefore, a data register must be set in the controller.

K9203 996920302  HIMA 控制器处理器模块