The electromagnetic interference and mechanical vibration are easy to cause falseoutput of the PLC, thus resulting in trouble of the system.
电磁干扰、机械振动等因素易造成PLC误输出，引发系统故障。
2
When that condition is false, that is, the page counter is either less than the start page or greater than the end page, it does not write any output.
当那个条件为假(也就是说，页计数器的值小于起始页或大于结束页)时，则selpg不再写任何输出。
3
A false value for the ok variable triggers the script to output a VXML fragment that redirects the user to the addentry.vxml file that will ask the user to re-specify their appointment information.