Communications: electrical – Condition responsive indicating system – With particular system function
Reexamination Certificate
1998-03-09
2001-05-01
Pope, Daryl (Department: 2632)
Communications: electrical
Condition responsive indicating system
With particular system function
C340S870030, C340S870030
Reexamination Certificate
active
06225899
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a data transmission system in a cyclic digital transmission used in a monitoring station.
2. Description of the Related Art
FIG. 1
shows the structure of a monitoring system that communicates alarm data by means of this type of cyclical data transmission (hereinbelow abbreviated CDT) of the prior art. In
FIG. 1
, the monitoring system is made up of monitoring device
10
established at master station
1
, monitoring device
20
established at slave station
2
, and the circuit connecting the monitoring devices.
An alarm from a monitored device that is collected within slave station
2
is converted to message data at external interface
23
of monitoring device
20
and sent to table comparison section
22
. Table comparison section
22
compares message data sent from external interface
23
with CDT conversion table
24
and determines the word position in the assembly destination of alarm data.
In CDT conversion table
24
, message data are pre-defined by each word position in an assembly destination of alarm data.
FIG. 2
shows the format of the CDT conversion table. The CDT conversion table indicates by the numerical values of words and bits the CDT output positions in an assembly destination corresponding to message data of an alarm, and holds the combinations of all words and bits.
Monitoring device
20
then transmits alarm data of the determined word positions from CDT transmitter
21
to CDT receiver
11
of monitoring device
10
established at master station
1
. Fundamentally, the total number of words of a one-cycle portion (for example, 64 words, one word being made up of
13
bits) of alarm data are always outputted, but the number of output words can be altered by using output word setting section
25
to pre-set the number of words in one cycle.
This transmission of information between a master station and slave station by means of this type of CDT is always carried out cyclically, and assembly for CDT is carried out by basing the assembly of CDT output words on a fixed CDT conversion table in which assembly words are pre-defined for each item of message data of an alarm, and by always referring to the entire table for all words (64 words). The conversion process is therefore time-consuming, and as a result, there is the problem that recognition of the generation of an alarm is delayed at the master station, i.e., the host center monitoring device.
In monitoring systems of the prior art, the table must be rewritten for all words on the transmitting side and receiving side in cases of the addition or deletion of data of a table designating assembly words, such addition or deletion commonly accompanying increases or decreases in collected alarms. In monitoring systems of the prior art, moreover, in cases in which there are fewer categories of collected alarms than the total number of CDT output words per circuit, words are outputted for which no definition exists, resulting in the transmission of superfluous words. Although the number of output words can be altered by means of output word setting section
25
, this modification must be effected in advance.
SUMMARY OF THE INVENTION
The object of the present invention is to provide an efficient CDT data transmission system that enables both reduction of the number of items of table data in a CDT output conversion table as well as free setting of the addition or deletion of table data in word units.
The present invention includes a means that can make additions or deletions to the table for assembling to CDT an alarm collected from a monitored device in units of the content of each alarm message by designating word positions corresponding to message content; wherein this means, when comparing the table with collected alarm messages and determining output word positions, adds designations that are not to be compared with alarm messages to message data within table data, and in addition, determines words that are to be transmitted from word positions defined in the table.
The present invention provides a table setting section that produces a CDT output conversion table that designates word positions corresponding to an alarm message, and enables the flexible alteration or updating of alarm data in accordance with the increase or decrease of alarms collected from a monitored device by adding to or deleting from the CDT output conversion table only relevant alarm data and without updating data for all words. In addition, the present invention can, according to necessity, degenerate an alarm message or simultaneously degenerate an alarm message and reduce the number of items of table data that are to be compared.
In addition, because output word positions of data that are set in the CDT output conversion table are consulted and only words that are designated as output word positions are set in CDT transmitter
21
, the present invention can prevent the transmission of,unnecessary words, thereby enabling more efficient CDT data transmission.
The above and other objects, features, and advantages of the present invention will become apparent from the following description with references to the accompanying drawings which illustrate an example of the present invention.
REFERENCES:
patent: 5400246 (1995-03-01), Wilson et al.
patent: 62-2742 (1987-01-01), None
patent: 1-300641 (1989-12-01), None
patent: 5-83212 (1993-04-01), None
NEC Corporation
Pope Daryl
Young & Thompson
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