Programmable logic controller PLC runtime panic condition may occur, which result in an estimated loss of industrial production, therefore, first of all to know the causes of panic PLC, for troubleshooting the cause, a software or hardware error may cause the PLC to panic, introduced below:
(1) I/O tracking, PLC I/O error is detected automatically, and enter the STOP mode.
(2) the I/O is damaged, running a program to needs the feedback of I/O signals, not down to follow the instructions.
(3) expansion module (function, such as a/d) line interference or open.
(4) power supply disturbances or failures.
(5) the PLC module connection module and address allocation failed.
(6) the cable failure.
(1) triggers an infinite loop.
(2) the program overwrite the contents of the parameters of the system, but part is not initialized.
(3) protection program start: hardware protection, restrictions on the use of time (money back)
(4) data overflow, step size is too large, the watchdog (to modify the DOG).