System and method for managing time in automatic control equipment
A time management system that includes a first clock having a first counter operating on a first timebase, a second clock having a second counter operating on a second timebase identical to the first timebase and a third counter operating on a third timebase less than the second timebase. The time management system performs a resynchronization of the second clock after the main electrical power supply has been restored, this resynchronization including, on a modification of the first counter, loading the first counter into the second counter and in zeroing the third counter.
1. A time management method for automatic control equipment comprising:
counting, at a first clock having a first counter storing a first value, based on a first time base;
counting, at a second clock having a second counter storing a second value, based on a second time base identical to the first time base;
counting, at a third counter of the second clock, based on a third time base that is quicker than the second time base;
powering, at a main electrical power supply, the first and second clocks;
powering, at an auxiliary electrical power supply, the first clock in response to a main electrical power supply outage;
performing, at a central processing unit, a periodic synchronization between the first counter and the second counter by loading the second value of the second counter into the first counter when the first counter is different from the second counter; and
performing, at the central processing unit, in response to the main electrical power supply being restored, a resynchronization of the second clock, based on a modification of the first counter, by loading the first value of the first counter into the second counter and zeroing the third counter
wherein
the first clock is based only on the first time base, and
the second clock is based only on the second and third time bases.
2. The time management method according to claim 1 , wherein the resynchronization is performed in response to a detection of a next change in the first counter after the main electrical power supply is restored.
3. The time management method according to claim 1 , wherein the first clock is a hardware component of a Real Time Clock type.
4. The time management method according to claim 1 , wherein the first time base is in seconds.
5. The time management method according to claim 1 , wherein the second clock is incremented by software.
6. The time management method according to claim 1 , wherein the third time base is in milliseconds.
7. The time management method according to claim 1 , wherein the auxiliary electrical power supply is a capacitor.
8. The time management method according to claim 1 , wherein the periodic synchronization is performed on a basis of the second counter of the second clock.
9. A time management system for automatic control equipment comprising:
a first clock having a first counter configured to operate on a first time base, the first counter storing a first value;
a second clock having a second counter configured to operate on a second time base identical to the first time base and a third counter configured to operate on a third time base that is quicker than the second time base, the second counter storing a second value;
a main electrical power supply configured to power the first and second clocks;
an auxiliary electrical power supply configured to power the first clock in response to a main electrical power supply outage;
a central processing unit configured to
periodically synchronize the second counter and the first counter by loading the second value of the second counter into the first counter when the first counter is different from the second counter, and
perform a resynchronization of the second clock after an end of a main electrical power supply outage, based on a modification of first counter, by loading the first value of the first counter into the second counter and zeroing the third counter
wherein
the first clock is based only on the first time base, and
the second clock is based only on the second and third time bases.
10. The time management system according to claim 9 , wherein the first clock is a hardware component of a Real Time Clock type.
11. The time management system according to claim 9 , wherein the first time base is in seconds.
12. The time management system according to claim 9 , wherein the second clock is controlled by software.
13. The time management system according to claim 9 , wherein the third time base is in milliseconds.
14. The time management system according to claim 9 , wherein the auxiliary electrical power supply is a capacitor.
15. A time management system for automatic control equipment comprising:
first counting means for counting, at a first counter storing a first value, based on a first time base;
second counting means for counting, at a second counter storing a second value, based on a second time base identical to the first time base and for counting, at a third counter of the second counting means, based on a third time base that is quicker than the second time base;
power supply means for powering the first and second counting means;
auxiliary power supply means for powering the first counting means in response to a power supply means outage;
processing means for
periodically synchronizing the second counter and the first counter by loading the second value of the second counter into the first counter when the first counter is different from the second counter, and
performing a resynchronization of the second counting means after an end of a power supply means outage, based on a modification of first counter, by loading the first value of the first counter into the second counter and zeroing the third the third counter
wherein
the first counting means is based only on the first time base, and
the second counting means is based only on the second and third time bases.