船舶电气英语求助1 The working principle and hardware block diagram T

船舶电气英语求助
1 The working principle and hardware block diagram
The system mainly consists of the single chip computer,the keyboard,the monitor,sensors,the signal-transform circuit,the signal-processing circuit,the alarm circuit and the printer .Fig .1 is the hardware block diagram.
According to Fig .1,the single chip computer INTEL 87C51 is the nucleus of the whole system which monitors the states of all switching sensors and the signals coming from analog sensors and digital sensors
There are 96-way signals coming from switching sensors that are formerly switching-on.The signals are connected to a port of the single chip computer INTEL87C51 by multi-channel switches and the optical isolator .The multi-channel switches are made up of six 16-channel analog switches CD4067.The number of port allotted by the system is 80H-0DFH.It is different from general port address that comes from the address bus because it comes from the signals on the data bus locked by 74HC373.After decoded by decoder 74HC138,the four high-bits of the signal locked provide the six analog switches with enabling signals,while the highest bit is valid when high voltage is the decoder’s enabling signal that decides if the decoder will work.The output signals of six multi-channel switches are connected with the single chip computer through the optical isolator .