S7-400系统在正常工作中出现EXTF故障指示灯亮,PLC处于STOP状态,用STEP7在线监控,CPU诊断缓冲区中显示内容如下:
Event 13 of 120: Event ID 16# 494D
STOP caused by I/O error
No relevance for user (Z1): 940a
No relevance for user (Z2): 0000 (Z3): 0000
Previous operating mode: RUN
Requested operating mode: STOP (internal)
External error, Incoming event
此时只有将PLC电源关断,重新启动,有时故障可消除,有时不能消除.系统CPU型号为CPU414-2DP,主机架为18槽,带有一18槽扩展机架.
不知故障出在何处,恳请各位高手指教.