Data processing: generic control systems or specific application – Generic control system – apparatus or process – Sequential or selective
Reexamination Certificate
2001-12-21
2004-06-22
Patel, Ramesh (Department: 2121)
Data processing: generic control systems or specific application
Generic control system, apparatus or process
Sequential or selective
C700S014000, C700S033000, C700S039000, C700S046000, C700S274000, C137S094000, C236S0150BG, C236S01500E, C237S00200B, C237S00200B, C237S00800C
Reexamination Certificate
active
06754541
ABSTRACT:
BACKGROUND OF THE INVENTION
Certain types of systems for controlling devices have adjustable settings for control parameters. It is common for these settings to be adjusted by a human operator. A very simple example is the thermostat found in nearly every occupied space. Such settings define either implicitly or explicitly, a control range for the control parameter. The control range is defined by an upper value and a lower value, within which the control system attempts to hold the control parameter by altering a control variable for the device. In the thermostat example, the control variable is usually an on or off signal for the heating plant.
For a variety of reasons, many of these control systems require limits for these control parameter settings. For example, a thermostat might for energy efficiency be designed or programmed to prevent settings outside of a desired temperature range. In other systems, an ultimate maximum (or minimum) value is assigned to a particular parameter for reasons of safety, durability, etc. An example of such a situation (and the one concerning the inventors) involves setting maximum pressure for a boiler.
Every boiler has as one of its critical parameters, a maximum pressure that for safe operation must never be exceeded. Other types of operating systems have other parameters for which an ultimate value must be assigned. In the case of boilers, this maximum allowable pressure will be referred to as the ultimate pressure, and other similar parameter values in other types of systems as ultimate parameter values.
In the case of boiler operation, it is customary to set a maximum operating pressure for the range of allowable pressure levels that is lower than the ultimate pressure. The reasons for this include greater fuel and operating efficiency and increased lifetime for the individual boilers. One system now in use sets the maximum operating pressure and the ultimate pressure for boilers with a maximum pressure potentiometer having a scale for selecting settings. The position of the potentiometer selects the maximum operating pressure, and overrides the control range upper value if set above the maximum operating pressure. A cam or stop on the potentiometer sets the ultimate pressure. When boilers are inspected for safety, the position of the stop on the maximum pressure potentiometer is checked. If higher than the ultimate pressure, the boiler and its operator are in violation, for which a variety of sanctions may be imposed.
There are a number of problems with this system. Potentiometers are electromechanical devices and can fail or drift with respect to the scale over time either with use or with disuse. Tampering with either the ultimate pressure stop or the maximum operating pressure is fairly easy even though access to the potentiometer stop is typically made somewhat difficult.
In electronic control systems, it is cheaper and more reliable for the controller itself to provide the ultimate pressure setting. However, this creates the problem that inspectors (and conscientious operators themselves) cannot easily determine the ultimate pressure setting since most electronic controllers have only rudimentary status indicators. In order to effectively implement ultimate pressure limits in electronic controllers, it is necessary to provide a means for communicating the settings.
BRIEF DESCRIPTION OF THE INVENTION
We have devised a control system providing a control signal for controlling the activity of an operating system. Our control system sets a system parameter by using a manually adjustable data generation device nominally used to provide a control value signal changing as the data generation device is manually adjusted. The control value signal is often a set point, and in the operating system for which this control system was developed, the set point is a pressure value of a boiler. Controlling the amount of heat energy provided to the boiler by a burner controls boiler pressure. The control signal adjusts the heat output of the burner by regulating the amount of fuel flowing to the burner.
This control system comprises a configuration flag memory element recording a configuration flag having at least first and second values and providing a configuration flag memory signal encoding the configuration flag value. In the embodiment we envision, the configuration flag will be set to its first value at the factory.
A first memory element receives the control value signal and the configuration flag memory signal, and at some point records the control value signal as the system parameter responsive to the first value in the configuration flag memory signal. The first memory element provides a first memory signal encoding the recorded system parameter. For purposes of defining the invention, the first memory element includes not only the data storage components for recording the system parameter, but may also include the control components for processing the signals it receives to effect proper storing of the system parameter.
A second memory element receives the control value signal and records as a set point value, the control value signal. The second memory element provides a second memory signal encoding the recorded set point value.
A control element receives the first and second memory signals, and provides a control signal based on the first and second memory signals and that is usable by the operating system for controlling its operation.
In one version of this invention, the first and second memory signals may be pressure values. The control element uses the first memory signal to set a maximum or safety value for the operating system pressure. The set point value can be changed during normal operation of the operating system by adjusting the data generation device. The maximum pressure value typically varies from system to system, and so cannot be set at the factory. Instead the installer permanently sets the maximum pressure or other system parameter during system installation.
To provide for user communication with the operating system, a reset switch forming a part of the control system provides a reset signal responsive to manual operation thereof. During normal operation the reset switch is used to reset (restart) the system either during testing or after an error or other failure results in the control element locking out normal operation.
During initialization of the system, the first memory element receives the reset signal. The first memory element records the control value signal as the system parameter responsive to the combination of both the first configuration flag value in the configuration flag memory signal and the reset signal from the reset switch.
During an operating system installation procedure, some adjustment and experimentation is typically required to properly set the system parameter. Frequently, the installer will need to watch system operation for a time, and then perhaps change the system parameter. To accommodate such installation procedures, the configuration flag memory element includes a timer element recording a timer value. The control system frequently changes the recorded timer value to indicate elapsed time. The timer memory element provides a timer signal encoding the current timer value. The first memory element receives the timer signal, and records the control value signal as the system parameter responsive to the combination of the timer value falling within a preselected range and an occurrence of the reset signal. The operation of these elements can be used to establish after initializing the system parameter for the first time, a grace period within which the installer can alter (reset) the value of the system parameter.
In a preferred embodiment, the timer element receives the timer signal and sets the timer value recorded in the timer element to a preselected initial value within the preselected range of the timer value responsive to the combination of the timer value falling within a preselected range, and the reset signal. The effect of this combination of functions is to reinitializ
Bartels James I.
O'Leary Scott P.
Solosky Richard M.
Honeywell International , Inc.
Patel Ramesh
LandOfFree
Control system apparatus for loading a value of a system... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Control system apparatus for loading a value of a system..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Control system apparatus for loading a value of a system... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3366242