S7-400 桥吊能正常作业，但是故障一直在，请各位大侠帮忙看看！！！
Event 1 of 57: Event ID 16# 39B1
I/O access error when updating the process image input table
P area, double-word access, access address: 620
process image partition no.: 0
not user relevant(Z1): 2942
Requested OB: Program execution error OB (OB85)
Priority class: 25
External error, Incoming event
04:02:30.279 PM 01/25/2013
这个故障一直报！~！！！！！！！！