Remote subsystem - Patent Review 4703325

We claim:

1. A remote subsystem for monitoring the status and performance of at least one unit of equipment at a remote site by periodically monitoring the states of a plurality of discrete parameter signals, associated with each unit of equipment, each related parameter signal being indicative of a like plurality of unit status parameters, said remote subsystem transmitting periodic messages indicative of the equipment status and performance to at least one related office, comprising:

signal processor means, responsive to the discrete parameter signals and having memory means for storing signals indicative of a previously monitored state of each periodically monitored discrete parameter signal, wherein selected discrete signals each having normal and abnormal states indicative of normal and abnormal conditions, respectively, are related in alarm groups, each group corresponding to a particular unit of equipment, said signal processor means comparing the presently monitored state of each discrete signal with a previously stored state of that signal for detecting a state change therebetween, said signal processor providing an alarm status signal for only the first discrete signal in an alarm group of related discrete signals to change state from a normal state to an abnormal state, said alarm signal being indicative of an associated abnormal condition in said corresponding unit of equipment, said signal processor providing a return to normal signal upon detecting a change in said first discrete signal from the abnormal state to the normal state only if all said discrete alarm signals in said related alarm group are presently in the normal state; and

communication element means, responsive to said alarm signal and said return to normal signal for transmission thereof to a related office.

2. The remote subsystem of claim 1, further comprising display means, responsive to said alarm status signal for displaying an alarm message describing said corresponding equipment alarm condition and responsive to said return to normal signal for displaying a return to normal message.

3. The remote subsystem of claim 1, wherein said communication element means transmits said alarm and return to normal signals to both a local office and a central office.

4. The remote subsystem of claim 1, wherein said signal processor additionally provides said alarm signal only if said first discrete signal remains in said changed state for a selected period.

5. The remote subsystem of claim 1, wherein said signal processor provides additional alarm signals for said first signal to change state only after all of said discrete signals in said group have returned to normal and said return to normal signal has been provided to said communication element means.

6. The remote subsystem of claim 1, wherein said signal processor inhibits additional alarm and return to normal signals associated with a particular equipment for a chosen interval after providing an immediately preceding alarm signal associated with that particular equipment except that a return to normal signal associated with the initiating alarm signal for said particular equipment is not inhibited.

7. The remote subsystem of claim 1, wherein said signal processor records over a period, the total time said corresponding unit remains in said alarm condition and periodically provides a signal indicative thereof via said communication element means for transmission to said office.

8. The remote subsystem of claim 1, wherein said signal processor periodically accumulates the number of occurances of alarm conditions for each unit and periodically provides a signal indicative thereof via said communication element means for transmission to said office.

9. The remote subsystem of claim 1, further comprising means for detecting said corresponding unit of equipment in an energized mode and providing an associated alarm enable signal indicative thereof to said signal processor means for inhibiting said alarm status signal unless said associated alarm enable signal is present.

10. The remote subsystem of claim 1, further comprising memory means for storing identification information relating to said subsystem and historical information relating to the past states of each of said parameter signals and further comprising clock means for monitoring the time of day and storing alarm time and duration information in said memory, wherein said alarm status signal provides identification of said remote subsystem, said communication element, said corresponding unit of equipment, said associated alarm condition, date and time of said change of state of said first signal, and date and time of transmittal of said alarm status signal via said communication element means.

11. The remote subsystem of claim 10, wherein said return to normal signal provides identification of said remote subsystem, said communication element, said corresponding unit of equipment, said associated alarm condition returned to normal, date and time of transmittal of said return to normal signal via said communication element means.

12. The remote subsystem of claim 1, wherein said signal processor records the number of state changes in a selected status signal and provides an alert signal to said communication element indicative of an impending abnormal condition in the presence of said recorded number exceeding a preset limit and wherein said communication element is responsive to said alert signal for immediate transmission to said related office.

13. The remote subsystem of claim 12, wherein only the first occurrence in a selected period of said recorded number exceeding a preset limit results in said processor providing said alert signal to said communication element for immediate transmission.

14. The remote subsystem of claim 13, wherein said signal processor counts all occurrences per day of said recorded number exceeding a preset limit and provides an alert count signal indicative thereof, and wherein said remote subsystem further comprises memory means for storing said alert count signal, and wherein communication element is responsive to said alert signal for periodic transmission to said related office.

15. The remote subsystem of claim 14, wherein said memory stores identification information relating to said subsystem and wherein said remote subsystem further comprises clock means for providing a time signal indicative of the time of day, said memory responsive to said time signal for storing the time of occurrence of each alert signal and wherein said communication element is responsive to said stored time signal for periodic transmission to said related office.

16. The remote subsystem of claim 1, wherein said signal processor is responsive to status signals indicative of operating equipment data including run condition, starts, stops and cycles and provides data signals indicative thereof to said communication element which is responsive to said data signals and periodically transmits said data signals to said related office.

17. The remote subsystem of claim 1, wherein said signal processor accumulates, during a selected period, the value of all parameter signals that changed state during said selected period and periodically provides a period summary signal indicative of the accumulated signals' values during said selected period to said communication element which is responsive to said summary signal and periodically transmits said summary signal to said related office.

18. A system for monitoring a plurality of remote subsystems, each remote subsystem monitoring the status and performance of at least one unit of equipment at an associated remote site by periodically monitoring the states of a plurality of discrete parameter signals, associated with each unit of equipment, each related parameter signal being indicative of a like plurality of unit status parameters, said remote subsystem transmitting periodic messages indicative of the equipment status to at least one related office, comprising:

plural remote subsystem signal processor means, each responsive to the associated equipment's discrete parameter signals and having memory means for storing signals indicative of a previously monitored state of each periodically monitored discrete parameter signal, wherein selected discrete signals each having normal and abnormal states indicative of normal and abnormal conditions, respectively, are related in alarm groups, each group corresponding to a particular unit of equipment, each signal processor means comparing the presently monitored state of each discrete signal with a previously stored state of that signal for detecting a state change therebetween, each signal processor providing an alarm status signal for only the first discrete signal in an alarm group of related discrete signals to change state from a normal state to an abnormal state, said alarm signal being indicative of an associated abnormal condition in said corresponding unit of equipment, each signal processor providing a return to normal signal upon detecting a change in said first discrete signal from the abnormal state to the normal state only if all said discrete alarm signals in said related alarm group are presently in the normal state; and

plural remote subsystem communication element means, each responsive to said alarm signal and said return to normal signal from its associated signal processor for transmission thereof to a related office;

plural service office communication element means, at least one for each service office, responsive to said alarm signal and said return to normal signal transmitted from each of said remote subsystem communication element means for providing each of said alarm signals and said return to normal signals; and

service office display means, responsive to said alarm signals and said return to normal signals from said service office communication element means, for displaying alarm and return to normal messages corresponding to each alarm and return to normal condition detected for each monitored device.

19. The system of claim 18, wherein each of said plural service office communication element means further comprises means for retransmitting each of said alarm signals and said return to normal signals and wherein said apparatus further comprises:

central office communication element means responsive to said retransmitted alarm signal and said retransmitted return to normal signal for providing said alarm signal and said return to normal signal; and

central office display means, responsive to said alarm signals and said return to normal signals from said central office communication element means, for displaying alarm and return to normal messages corresponding to each alarm and return to normal condition detected for each monitored device.

20. The system of claim 19, wherein selected ones of said plural service office communication element means are responsive to said alarm signals from a number of said related remote subsystem communication element means for transmission to said central office display means.

21. The remote subsystem of claim 1, further comprising sensor means responsive to said status parameters for providing the discrete parameter signals.

22. The system of claim 18, further comprising sensor means responsive to said status parameters for providing the discrete parameter signals.

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DESCRIPTION

1. Technical Field

This invention relates to monitoring selected parameters of a plurality of operating devices at a plurality of remote sites, for alerting responsible personnel of significant conditions.

2. Background Art

Any number of devices operating at a plurality of remote sites may be monitored using intelligence gathered at the remote sites and transmitting information on the present status of the sensed parameters during the device's operation at the sites. The parameters selected for monitoring are chosen according to their importance in evaluating the operational condition of a device. In the case of an HVAC system, for example, typical sensors in a chiller, would include evaporator pressure, compressor discharge temperature, chill water flow, condensor water flow, and oil temperatures. These sensors produce signals which may be multiplexed into a transmitter for transmittal to a local office which monitors the status of the plurality of systems. Upon receiving a signal indicating an abnormal condition, the local office personnel may logically infer the operational condition of the system by noting the presence or absence of other abnormal condition signals or other associated sensor parameters.

Generally, the more information received, the more accurate the conclusions that may be drawn concerning the nature of conditions. Once a conclusion is drawn, a service man is then dispatched to the remote location having at least some foreknowledge of the nature of the inoperative condition which permits him to make adequate preparations for quickly correcting the condition.

As the number of monitored parameters increases, the task of evaluating whether and what kind of an alarm condition exists, if any, becomes more difficult. If a local office is monitoring a large number of systems, the amount of performance information received can be very high making the interpretative task even more difficult.

An additional difficulty in using large numbers of monitored parameters is that the interpretative task can become extremely complex, making it likely that the interpretative errors or oversights may occur. If such an error or oversight occurs, the owner of the building in which the inoperative HVAC device is located will eventually telephone requesting a serviceman and providing whatever knowledge he may have concerning the nature of the inoperative condition. However, this is a highly undesirable form of receiving the information needed to efficiently deploy a service organization. This is especially true when a monitoring system has been installed in a building for the purpose of immediately detecting such inoperative conditions at a local service office.

Inventor Charles Whynacht invented a REMOTE ELEVATOR MONITORING SYSTEM, U.S. Pat. No. 562,624, assigned to a co-owned company, which monitors a large number of remote sites at locals and a central and which solves, for some types of systems including elevators, the above described problem. The object of the Whynacht invention was to provide an operating system monitor capable of monitoring parameters and evaluating their states in order to form conclusions concerning the system's performance and to determine whether any predefined alarm conditions were present. According to the Whynacht invention the sensed parameters were stored by a signal processor and compared to previously received values in order to determine if any parameters had changed state. If so, the present value of the changed parameter(s) was (were) plugged into a Boolean expression defining an alarm condition in order to determine if the Boolean expression was satisfied and hence the alarm condition was present. If so, an alarm condition signal was transmitted and displayed as an alarm message.

In addition, the Whynacht invention embraced a group of monitored systems in, for example, a particular geographical area and monitored the various individual systems at a central location in the local geographical area so that appropriate area service actions could be effectively managed. In addition, the Whynacht invention disclosed that many local offices may be grouped together into an overall group which all transmit their data to a headquarters office which monitors many local offices in different geographical areas.

Unfortunately, the Whynacht invention does not reduce the number of alarms received for certain types of systems, e.g., HVAC, in which the Boolean expressions for alarms using combinational logic may not be particularly complex and in which in fact many of the alarms may be unconditional or conditioned merely on the existence of a run state. Another means of reducing the number of alarms without sacrificing accurate detection of alarm conditions is needed for such systems.

DISCLOSURE OF INVENTION

The object of the present invention is to provide improved apparatus for monitoring the status and performance of mechanical and electrical equipment by monitoring selected parameters indicative of the present operating condition of the device and evaluating the parameter states in order to form accurate conclusions concerning the device's current and future performance to a high degree of certainty and to form equally accurate conclusions concerning whether any predefined alarm or alert conditions are present.

According to the present invention the values of particular sensed parameter signals to be evaluated in an alarm group are periodically sampled and stored by a signal processor which compares the present sampled values with values sampled and stored at an earlier time to determine if any parameter signal in the group has changed state, and if so, providing an alarm signal only for the first detected signal in the group that changed state. The alarm signal is transmitted, typically by a modem, to a related office, typically a local office. The alarm signal may also be transmited to a central office.

In further accord with the present invention, the alarm signal may be used by a display to provide an alarm message. When all of the sensed parameter signals change back to a normal operating state, a return to normal signal is provided to the display which then provides a return to normal message.

In still further accord with the present invention, the signal processor may be programmed to provide an alarm signal only if a selected monitored device is detected in a run mode.

In still further accord with the present invention, the signal processor may be programmed to provide the alarm signal only if a selected monitored device has been detected in a run mode for a selected period.

In still further accord with the present invention, the signal processor may be programmed to provide the alarm signal only if the first discrete signal which has been detected in a changed state, remains in that changed state for a selected period.

In still further accord with the present invention, the signal processor may be programmed to provide additional alarm signals for the first signal to change state only after all of the discrete signals in the alarm group have returned to normal and a return to normal signal has been provided to the modem. The signal processor may also inhibit additional alarm and return to normal signals for a particular piece of equipment for a chosen interval after providing an alarm signal for that particular piece of equipment. Of course, a return to normal signal associated with the initiating alarm signal for the particular piece of equipment is not inhibited.

In still further accord with the present invention, the signal processor may be programmed to record over a period, for example, one day, the total amount of time that the alarming unit remains in an alarm condition and periodically provides a signal indicitive of the total time to the modem for transmission. The number of occurances of alarm conditions for each unit over the same period or any other period may also be periodically provided to the modem for transmission.

In still further accord with the present invention, the remote subsystem may also include memory for storing identification information relating to a particular subsystem and for storing historical information relating to the past states of each of the parameter signals monitored within the particular subsystem. The remote system may also include a timer for monitoring the time of day and storing the time and duration of alarm conditions. The alarm status signal may include such information so that the identity of the subsystem, the particular unit of equipment in an alarm state, the nature of the alarm condition, the date and time of the change of state of the first signal to change, and the date of time of transmission may be provided via the modem. Of course the return to normal signal can also be configured to provide similar identification and timing information.

In still further accord with the present invention, the performance of a unit or device is monitored by counting the number of state changes in a particular parameter signal and providing a performance alert signal only after the detection of a selected number of such state changes.

In still further accord with the present invention, the signal processor provides a performance alert signal only if a selected number of state changes are counted within a selected elapsed time interval.

In still further accord with the present invention data points are monitored to serve as the basis for run mode dependancy relationships with other points on the same equipment. The total number of occurrances and totalized time of occurance per day for each data point is accumulated and buffered for batch transfer with similar alert data. Data points also serve as monitored points for exceedance alerts.

In still further accord with the present invention, all daily counts and totalized time for each discrete alarm, alert and data point will be accumulated and retained temporarily by the remote subsystem as "Daily Summary Data". It will be transmitted either automatically each day at a selected time (phased with other remote subsystems within a local office's jurisdiction), or automatically once a week at a selected day and time with accumulated daily segments, or only by command from the appropriate office, if and when it is wanted.

The remote system monitor of the present invention provides an intelligent means of automatically evaluating the operational status of an operating system. It also may be used for automatically evaluating the status of a plurality of systems organized in local geographical areas each reporting to an associated local office. The demanding task of evaluating many hundreds, thousands, or hundreds of thousands of performance data is greatly reduced by providing only the first alarm to be sensed and only significant alert conditions in a message to be displayed. This automatically reduces the quantity of received messages and data while at the same time providing valuable information as to the probable source of the problem. Knowledge of the first alarm condition to actuate is necessary in inferring the probable source of trouble. The automatic provision of alarm messages to the local office insures that proper evaluation of the messages leads to efficient deployment of the local office service force. In this way, the quality of services performed for the equipment customer is greatly improved. In many cases, a deteriorating or deleterious condition may be detected by means of alerts before it causes an equipment disablement. In cases where a disablement has occurred, the nature of the problem can often be identified by means of alarms before dispatching the serviceman so that the nature of the corrective action required may be determined in advance. Local and central office personnel may also be kept informed as to performance by means of data, operating problems, and disablements in all field equipment. This provides an extremely valuable management tool for the headquarters operation. Personnel at the central monitoring center are able to closely monitor the performance of essentially all of the equipment in the field. A continuation of field service response may then be assured, even when the field offices are not occupied, which may be a considerable amount of a normal work week.

Performance trends may be detected and accurate forecasts devised for use in business planning. The instantanous nature of the knowledge provided as to the effectiveness of the service force in remedying field problems is also an invaluable aid to management in identifying and correcting local service offices having unsatsfactory service records. When retransmitted to a central office, essential information necesary for long term performance projections and for the evaluation of the effectiveness of local service offices is provided for use by central office personnel.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a system block diagram of a remote subsystem monitoring system according to the present invention;

FIG. 2 is a second, alternative, system block diagram of a remote subsystem monitoring system (showing only one subsystem) according to the present invention;

FIG. 3 is a flowchart illustration of an alarm task routine;

FIG. 4 is a flowchart illustration of an alarm subroutine;

FIG. 5 is a flowchart illustration of an alarm time out subroutine;

FIG. 6 is a flowchart illustration of a return to normal subroutine;

FIG. 7 is a flowchart illustration of an inspect task routine;

FIG. 8 is a flowchart illustration of a timer task subroutine;

FIG. 9 is a flowchart illustration of a logic subroutine;

FIG. 10 is a flowchart illustration of a count task routine;

FIG. 11 is a flowchart illustration of an alert check subroutine;

FIG. 12 is a flowchart illustration of an exceedance subroutine;

FIG. 13 is a flowchart illustration of a LURGI subroutine;

FIG. 14 is a flowchart illustration of an AARGH subroutine;

FIG. 15 is a flowchart illustration of a time task routine;

FIG. 16 is a flowchart illustration of a clear subroutine;

FIG. 17 is a flowchart illustration of a run task routine;

FIG. 18 is a flowchart illustration of an autotask routine;

FIG. 19 is a flowchart illustration of an enable task routine; and

FIG. 20 is a flowchart illustration of an enable task routine.

BEST MODE FOR CARRYING OUT THE INVENTION

FIGS. 1 & 2 both illustrate a remote subsystem 8 monitoring system 10, according to the present invention, for monitoring equipment, individual operating units, or devices in remotely located buildings 12, and for transmitting alarm, alert and performance information to associated local monitoring units 14. In both FIGS. 1 & 2 the transmitted information is ultimately provided to a central monitoring center 16. However, the flow of information in FIG. 1 is from the remote subsystem 8 to the local office 14 and on to the central office 16. In FIG. 2, the flow of information is from the remote subsystem 8 to the local office 14, to a host main frame computer 17 for processing and then back to both the field office 14 and on to the central office 16. FIG. 2 additionally shows backup phone connections on lines 17a, 17b from the remote subsystem 8 and the field office 14, respectively, to the central office 16.

The method of communication between the remote buildings 12, the various local offices 14, and the centralized office 16 may be any viable communication system whereby inoperative equipment, operating units, or devices are identified and individual device performance information is transferred to both local and/or central offices. Such a system may include local telephone lines, microwave transmission methods, dedicated phone lines, or any similar systems or combinations thereof. Each remote subsystem 8 may include a master 18 and one or more slaves 20. The individual slaves are attached to sensors associated with a particular equipment, unit, or device. The slaves transmit signals indicative of the status of selected parameters via a communications line 22 which may consist of an unshielded pair of wires. The use of a two wire communications line between the master 18 and its associated slaves 20 provides an inexpensive means of data transmission.

Each master includes a microprocessor which evaluates the performance data and determines whether any significant conditions exist according to a state machine model