System for time stamping events using a remote master clock
First Claim
1. A system for time-stamping events using a remote master clock, said system comprising:
- a slave station including;
detection means detecting the occurrence of a predetermined event;
pulse generating means generating clocking pulses at predetermined timed intervals; and
counting means responsive to detection by said detection means of said predetermined event to initiate a count of said clocking pulses;
communications means transmitting said count in response to a send command;
means generating said send command; and
a master station including;
a master clock maintaining absolute time; and
processing means responsive to said master clock and said count transmitted by said communications means for calculating an absolute time at which said predetermined event occurred from said count, the absolute time maintained by the master clock, the predetermined time interval between clocking pulses, and a transmission time representing the time required for transmission of said count from said slave station to said master station over said communication means.
2 Assignments
0 Petitions
Accused Products
Abstract
Events at spaced locations, such as contact activity in the protective relays of an electric power distribution network, are time stamped using a single remote clock by a system which includes one or more slave stations monitoring the events. Each slave station initiates a count of locally generated clocking pulses of fixed duration upon detection of the first event monitored by it. Identification of the first event is stored in a first slot in memory. Additional memory slots each store the identification of a subsequent event and the count at the occurrence of that subsequent event. Upon command from a remote master station, the current count is stored in the first slot and the contents of the first slot and of the additional slots are transmitted over a communications network to the master station. The master station calculates the absolute time of each event using its master clock, the transmitted counts, the fixed duration of the clocking pulses, and the transmission time required to transmit the data from the particular slave station to the master station. The master station then sends a clear command to reset the count and clear the memory slots. If the number of events detected by a slave station before a clear command is received exceeds the number of memory slots available, the information on the first event stored in the first slot is retained, and the additional slots retain data on as many of the most recent events as there are additional slots.
-
Citations
16 Claims
-
1. A system for time-stamping events using a remote master clock, said system comprising:
-
a slave station including; detection means detecting the occurrence of a predetermined event; pulse generating means generating clocking pulses at predetermined timed intervals; and counting means responsive to detection by said detection means of said predetermined event to initiate a count of said clocking pulses; communications means transmitting said count in response to a send command; means generating said send command; and a master station including; a master clock maintaining absolute time; and processing means responsive to said master clock and said count transmitted by said communications means for calculating an absolute time at which said predetermined event occurred from said count, the absolute time maintained by the master clock, the predetermined time interval between clocking pulses, and a transmission time representing the time required for transmission of said count from said slave station to said master station over said communication means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
-
-
13. In an electric power distribution network having a plurality of protective relays each with at least one electrical contact operated in response to conditions in said network detected by the relay, a system for remotely determining the absolute time of operation of said contacts comprising:
-
a plurality of slave stations each including; means detecting the operation of and identification of at least one contact of at least one of said protective relays; means generating clocking pulses at a fixed time interval common to all slave stations; means responsive to said detection means for initiating a count of said clocking pulses in response to operation of a first of said contacts; and storage means for storing information in slots including a first slot for storing the identification of the first contact and in response to a send command the total count at the time of said send command, and additional slots each storing the identification of a contact subsequently operated and the count at the instant such contact is subsequently operated; a communications network over which each slave station sends in response to said send command the information stored in the first slot, and in said additional slots; and a master station connected to said communications network to receive said information sent from each slave station, and including; a master clock maintaining a current absolute time; means generating said send command; and processing means determining the absolute time of the operation of each contact from said total count, the counts stored in said additional slots, said fixed time interval, said current absolute time, and a transmission time for transmitting the information from the slave station in which it is stored to the master station. - View Dependent Claims (14, 15, 16)
-
Specification