System and operating states of the S7–400H
11.3 The operating states of the CPUs
S7-400H
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System Manual, 03/2012, A5E00267695-11
4.
If a multiple-bit error occurs on a CPU in redundant mode, that CPU will enter ERROR-
SEARCH mode. The partner CPU assumes master mode as required, and continues
operation in standalone mode.
But: OB 84 is called if 2 single-bit errors occur on a CPU in redundant mode within 6
months. The CPU does not change to ERROR-SEARCH mode.
5.
If synchronization is lost during redundant mode, the standby CPU changes to ERROR-
SEARCH mode. The other CPU remains master and continues operation in standalone
mode.
The purpose of ERROR-SEARCH mode is to find a faulty CPU. The standby CPU runs the
full self-test, while the master CPU remains in RUN. If a hardware fault is detected, the CPU
changes to DEFECTIVE state. If no fault is detected the CPU is linked up again. The fault-
tolerant system resumes the redundant system state. An automatic master-standby
changeover then takes place. This ensures that when the next error is detected in error-
search mode, the hardware of the previous master CPU is tested.
No communication is possible, e.g. by means of access from a programming device, while
the CPU is in ERROR-SEARCH operating state. The ERROR-SEARCH mode is indicated
by the RUN and STOP LEDs, see section Status and error displays (Page 55).
For additional information on the self-test, refer to section Self-test (Page 137)
Содержание SIMATIC S7-400H
Страница 24: ...Preface 1 1 Preface S7 400H 24 System Manual 03 2012 A5E00267695 11 ...
Страница 46: ...Getting Started 4 5 Special layout features of SIMATIC Manager S7 400H 46 System Manual 03 2012 A5E00267695 11 ...
Страница 120: ...Memory concept 10 1 Overview of the memory concept of S7 400H CPUs S7 400H 120 System Manual 03 2012 A5E00267695 11 ...
Страница 258: ...Communication 14 8 General issues regarding communication S7 400H 258 System Manual 03 2012 A5E00267695 11 ...
Страница 354: ...Synchronization modules 18 3 Selecting fiber optic cables S7 400H 354 System Manual 03 2012 A5E00267695 11 ...
Страница 434: ...Technical data 20 6 Runtimes of the FCs and FBs for redundant I Os S7 400H 434 System Manual 03 2012 A5E00267695 11 ...
Страница 460: ...Function modules and communication processors supported by the S7 400H S7 400H 460 System Manual 03 2012 A5E00267695 11 ...