我的cpu在启动一个工程之后，cpu突然stop，然后再也起不来，除非把工程块重新下载后软启动，才能恢复到运行状态，我检查程序好几遍都不能找到原因，请各位大侠帮忙提示一下，我有重点的去查找原因，谢谢！
这是报警代码：
Diagnostic buffer of module CPU 315-2PN/DP

Order No./ Des cription Component Version
6ES7 315-2EH14-0AB0 Hardware 2
- - - Firmware V 3.1.1
Boot Loader Firmware expansion A 26.7.7

Rack: 0
Slot: 2


Serial number: S C-AOV149302010


Event 1 of 500: Event ID 16# 4541
STOP caused by priority class system
Event: Cycle time exceeded
OB number: Timing error OB (OB80)
Priority class: 26
Previous operating mode: RUN
Requested operating mode: STOP (internal)
Internal error, Incoming event
07:08:17.973 AM 04/28/2011


Event 2 of 500: Event ID 16# 3501
Cycle time exceeded
Run time of the last cycle (ms): 150
Cause: Cyclic interrupt clock pulse generator 3
Causing OB: Cyclic interrupt OB (OB 32)
Causing priority class: 9
Requested OB: Timing error OB (OB80)
Priority class: 26
Internal error, Incoming event
07:08:17.823 AM 04/28/2011
帮助提示：
Possible causes:

?Overflow of an internal buffer when entering an asynchronous error OB request (only with the S7-400)

To correct or avoid errors:
Reduce the run time of the asynchronous error OBs or change the priority of individual asynchronous error OBs with STEP 7 (for example, assign OB81, OB82, OB83, OB86 and OB87 to priority class 24 or 25).


?The watchdog was triggered several times in quick succession.

To correct or avoid errors:
Reduce the scan time or retrigger the watchdog with SFC 43 "RE_TRIGR".


The time error OB (OB80) was requested several times although it was not yet been completely executed.

To correct or avoid errors:
Avoid time errors occurring in quick succession (for example, extend the cyclic interrupt intervals) or reduce the time required to service them.


?A hardware interrupt was set by a module although the previous interrupt for this module had not yet been serviced.

To correct or avoid errors:
Replace the module.

多谢大侠们的帮助，以下是我实验的:
当时我认为是初始化的时候临时变量只能保存一个周期，下一个周期就丢失了，从而opn【临时变量】时产生严重错误，后来我都改为了真实地址，发现仍然不能解决掉该问题，cpu仍然会在运行工程时死机。死机的原因是运行周期超过了硬件组态中的250ms，打到了500ms以上。
经过我仔细读程序，感觉可能是以下问题，希望大侠给些意见：
1.跳转_end时，可能超出了跳转的字节。在jc跳出的words计算中，调用的自己编辑的函数是不是也计算在32767之内，如果跳转命令超出32767编译时
是否报错？在编程的时候如何才能判断是否跳出32767的程序？
2.频繁的用opn打开不同的db块和频繁的用opn打开相同的db块，用指针进行操作，是否会影响cpu的运行周期，或者出现错误
3. L "Fast_Cooling".FTNO_in
T #Temp_Tank_in
OPN DB [#Temp_Tank_in]
L "Fast_Cooling".FT_inAmount
L "Fast_Cooling".FT_Beer
+R
T DBD 262
L 5
T "Fast_Cooling".StepNo


L "Fast_Cooling".FTNO_in
T #Temp_Tank_in
L "Fast_Cooling".FT_inAmount
L "Fast_Cooling".FT_Beer
+R
OPN DB [#Temp_Tank_in]
T DBD 262
L 5
T "Fast_Cooling".StepNo
这两段语句的opn位置是否有错误的地方导致cpu死机？
请高手指点！非常感谢！
急用！