Electrical computers and digital data processing systems: input/ – Intrasystem connection – Bus access regulation
Reexamination Certificate
1998-04-20
2001-01-30
Lintz, Paul R. (Department: 2768)
Electrical computers and digital data processing systems: input/
Intrasystem connection
Bus access regulation
C710S005000, C710S009000, C710S011000, C710S120000, C710S100000, C710S260000, C700S003000, C714S100000, C370S364000
Reexamination Certificate
active
06182179
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the field of distributed I/O systems, and more particularly, to a modular networked I/O system including a host computer and one or more module banks coupled via a network bus.
DESCRIPTION OF THE RELATED ART
In order to more efficiently and effectively address the problems associated with distributed sensing and control, providers of I/O devices and systems have evolved toward solutions which adhere to a common set of principles which include modularity, ease of configuration, and network operability.
For example, the 1794 Flex I/O product line manufactured by Allen-Bradley, a Rockwell Automation Business, comprises a modular I/O system for distributed applications. For more information concerning the Flex I/O product line refer to the Flex I/O Product Data Publication 1794-2.1 which is hereby incorporated by reference.
Another example is offered by the OpenLine™ product line manufactured by Grayhill, Inc. The OpenLine™ I/O system is a modular distributed control and data acquisition system. For more information concerning the OpenLineTM family of products refer to the OpenLine Product Data Bulletin #738 which is hereby incorporated by reference.
Prior art modular distributed I/O systems typically include a host computer coupled to one or more module banks through a network bus. The host computer sends command and configuration information to the module banks, and receives sensor data and status information from the module banks through the network bus. Each module bank generally includes a communication module, a plurality of terminal bases, and a plurality of I/O modules. The terminal bases couple together to form a communications backplane. The communication module generally couples to the first terminal base of the succession of terminal bases. The I/O modules are interchangably inserted into terminal bases. Each terminal base includes a host of connectors which provide the corresponding I/O module with connectivity to field devices. The communication module mediates communications between the network bus and the I/O modules comprising a module bank. The I/O modules occur in a variety of types for performing analog and/or digital I/O operations.
As mentioned above, the host computer sends configuration information to an I/O module in order to customize the functionality of the I/O module. However, a fundamental problem associated with the prior art distributed I/O systems is that this configuration information programmed into an I/O module is lost when the I/O module is removed from its terminal base. The time and effort expended in tuning the I/O module's configuration is wasted. Thus, a need exists for a modular distributed I/O system with the capacity to more adequately maintain I/O module configuration even during the physical absence of the I/O module from its terminal base.
In addition to the physical removal of an I/O module, configuration information may be lost in response to the loss of power to the I/O module. Thus, it would be very desirable to provide a method for (a) capturing the configuration state of an I/O module, and (b) restoring the captured configuration state to the I/O module, or to another I/O module of similar type, after a power-loss event.
Another issue of concern in modular distributed I/O systems, and in networked systems in general, is to provide mechanisms for safely and reliably responding to failures in network bus communications. To this end, it is desirable to provide within each communication module an activity monitor for sensing communication failure conditions on the network bus. Furthermore, since the distributed I/O system is controlled by a software application which runs on the host computer, there may be a period of network bus inactivity during the initial start-up phase while the host computer loads the software application. It is desirable that the activity monitors within the communication modules not interpret this initial period of network bus activity as a communication failure condition.
The primary function of the communication module is to mediate communications between the network bus and the local bus formed by the adjoined terminal bases. In order to maximize the communication capacity over the local bus, it is necessary for the local bus architecture to be optimized. In particular, since an I/O module may be interchangably inserted into any terminal base, a need exists for an automatic mechanism of assigning addresses to terminal bases. Furthermore, since the I/O modules, in the course of their operation, may send and receive different types of data, a need exists for a partitioned local bus architecture where distinct sections of the local bus are dedicated for different types of data transfer.
In response to continuing improvements in CPU and memory technology, communication modules are increasingly able to perform more sophisticated types of processing under software control. In view of the fact that the module bank may include multiple I/O modules of different types, a need exists for a communication module with multi-threaded processing capacity,
In order to perform the sensing and/or control tasks for which it is designed, an I/O module includes internal registers which may be read/written by the communication module as well as the I/O module. Thus, a mechanism for controlling read/write access to the internal registers is needed, and especially such a mechanism as would be compatible with the requirements of a communication module with multi-threaded processing capability.
SUMMARY
The problems and needs discussed above in the context of prior art modular distributed I/O systems are solved by the system and methods of the present invention. In particular, the present invention contemplates a method for maintaining the continuity of configuration information among multiple I/O modules which successively occupy a common slot (i.e. terminal base) in a distributed I/O system. The distributed I/O system includes a computer system coupled to at least one module bank. The module bank includes a communication module and one or more terminal bases which are in electrical contact with the communication module. The module bank also includes one or more I/O modules which are attached to corresponding terminal bases.
The method for maintaining configuration continuity includes the following steps. An I/O module is inserted into a terminal base of a module bank. The communication module reads configuration information stored in the I/O module. The stored configuration information comprises a data structure which serves to describe the functional characteristics and factory default settings for the I/O module. The communication module stores the configuration information in non-volatile memory as a “virtual module structure”. Furthermore, the communication module monitors configuration updates which are supplied to the I/O module and updates the stored configuration information (i.e. virtual module structure) accordingly. The virtual module structure is maintained as a continuous image of at least a subset of the registers within the I/O module. When the I/O module is removed and a subsequent I/O module is inserted into the same slot (terminal base), the communication module determines if the subsequent I/O module is compatible with the stored configuration information. If the subsequent I/O module is determined to be compatible with the stored configuration information, the configuration information is used to configure the subsequent I/O module. Thus, configuration continuity is maintained between the first I/O module and the second I/O module.
It is noted that the communication module continues to update the stored configuration information after the first I/O module has been removed and before the subsequent I/O module has been inserted. In other words, the communication module detects messages targeted for the first I/O module even in the physical absence of the first I/O module, and updates the virtual module structure to correspond to the contents of t
Foote Garritt W.
Mehta Pratik
Conley Rose & Tayon
Hood Jeffrey C.
Lintz Paul R.
National Instruments Corporation
Speight Jibreel
LandOfFree
System that is able to read and write using a transmission... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with System that is able to read and write using a transmission..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and System that is able to read and write using a transmission... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2462368