МПС 1

1.features of the designing of microprocessor systems

1.1 Technical requirements of MPS

MPS is a set of Hard Ware and Soft Ware[1]. Hard Ware provide maximal productivity and high performance and Soft Ware provides expansion of task’s range that are solved by the given MPS. as the rules realization of calculations by software’s methods is less performance. That’s why in a process of MPS designing it’s necessary to determine an optimal relation between characteristics of MPS. System performance, storage capacity, proportions, consumer energy are main criteria of MPS structure choice in the projection process.

A general criterion of MPS structure choice when the problem is solving as the rule is the value criterion that includes all mentioned criteria.

At MPS designing it is necessary to take into account following opportunities:

1. Real-time capturing and processing of different measuring parameters .

2. Preliminary conversion of various information.

3. Displaying of information in the form of form card with monitor’s connecting.

4. Control and evaluation of parameters and comparisons with standards.

5. Diagnostics and analyses of MPS operation with possibility of diagnostic programs calling.

6. Backup of huge amount of data with possibility of overview and analyzing.

7. Protocols execution on paper and magnetic carrier.

8. Linkage with other systems in the form of connection to LAN.

9. Producing of control signals for using in signalization system.

Technical features:

1. The structure of designing MPS must be typical and universal that reduces time for development of such system.

2. Providing of high speed of response at small consumption of energy.

3. Possibility to connect large amount of sensors and peripheral devices.

4. Small proportions and mass.

5. Law cost.

Constructional features :

1. Improved vent system and using of different filters.

2. Usage of double-way feed: alternating and direct.

3. Designing MPS must be a part of crate.

4. Protecting from crash.

5. Computability with whole set of effective devices.

1.2. Purpose and major components of MPVS

In general case a system of MPS(exchange) includes:

• multitude sources: D={D1,D2,…,Dn};

• multitude receivers : П= {П1, П2,…, Пn}.

In such way we have multichannel system of data transmission(SPT)

If microprocessor’s system provides data interchange it is called duplex.

General scheme is simplified to another scheme MPS operation with numerous measuring parameters(signals) and numerous control parameters (picture1.2)

Control object (CO) contains sensors D which forms multitude parameters S necessary for primary processing of information about object. Capturing of such information, conversation and entering in an operational block MPS are made by means of conversation subsystem that interacts with a core MPS through system interface. When necessary computing operations upon parameters S are fulfillment then operation block or core forms control action that is transferred to object to provide necessary processes’ features of control or measurement through output block and conversation block .

Results are displayed or transferred through communication bus to interact with high level systems, and for secondary processing of information.

To fulfillment purpose hardware must include the main nodes that are shown on the picture 1.3[4].

We can observe two types of information flaws in structure scheme. The first flaw – input and output data. The second flaw- commands of control over nodes and facilities.

Handled Information enters with the help of input device from sensors of control object. Purpose of input devices-conversation of information without changing of contents in a form acceptable for computer.

Results of handled information –output data- are transformed in a form acceptable for perception by operator or actuating apparatus of control object with the help of output device.

Information is transmitted through channel input-output from external devices to central and vice-versa. It is specialized processor where realized hardware and software of data transfer and control of input-output operations.

Connection is organized by two methods between multifunctional and specialized modules in MPS: by means of arbitrary connection realized principle “each with each”;and by means of ordered connections- long-haul communication.

Modem is used for modulation-demodulation of signals.

OVC Is used to save Reference information, large data arrays that are not take part in operation at the moment and also program tasks subject to fulfillment. Though OVC was bound to central devices and controlled by them in a design-wise is executed separately.

ALU is a part of a central processor , it forms functions of two input variable operands and generates one output variable. These functions cosist of simple arithmetic operations.

RAM is connected with processor. Programs commands and data are included in calculation at the moment are stored in RAM. There are written computed results before transmition to OVC or output devices.

N generates the stream of incoming data sequence of control signals coordinates combined work of all nodes and providing control by transmition of information between memory, ALU and computer. The main function of N is control fulfillment commands and operations.

The given system is closed and works automatically. MPS structure of handled information depends on the form of its input and output signals.

1.3. Principle tasks of MPS capturing information

In the design process necessary to solve number of tasks or distribution system of operations in different modifications when MPS construction approaches to control object.

There are distinguished 4 central tasks of handling.:

1. capture of information;

2. primary processing;

3. secondary processing;

4. presentation of control or measurement results and in the necessary case transmitting of this data through communication bus.

Capturing information includes:

1. inquiry of informational sources in the form of sensors making by the way of commutation of pulse-analog signals to transforming device(analog-code) or receiving digital data to processor’s block.;

2. convertation of analog form to digital;

3. synchronization of sensors’ signals with inputs transformating circuits; revelation and elimination of signal’s deviation from the given levels and specified parameters taking into account temporal relation.

4. Capturing in the form of registration of data storage and its displaying on indicative means.

Primary processing :

1. Linearization is realized by the calculation of linear functional dependence;

2. Scaling and introduction of (making) an amendment;

3. Calculation of corrected dependences;

4. Filtering , extrapolation , comparison of technical value of data with critical;

5. Calculation of current value of parameters;

6. Monitoring of rate of parameters changing with indication of critical value;

7. Generation of qualitatively new information by the way of compressure or decompressure.

Secondary processing:

1) as a secondary processing tasks can be used tasks of primary processing but for more accurate algorithms and software;

2) as a secondary processing can be used calibration, screening, compression etc.

Presentation of measuring and controlled results:

1) convertation of data convenient to transmition;

2) coordination of information and communication protocol for data transmission over the communication channels;

3) rate coordination of reception and transmission of information and realization of buffering.

1.4. Variants of MPS structure of capturing and information processing

There are 4 variants of organization of MPS structure (pict. 1.4) [14]

Variant A is a set of single-channel conversion systems offering a parallel transformation of the sensor channels with separate computing converters called adapters. Thus computing convertors together with form convertors of information presentation perform some logical and mathematical operations on the pre-treatment and the formation of the control actions on the control objects.

Variant B is a principle of consecutive signals processing of sensors through commutator . Thus adapter  is approached maximal to microprocessor what allows to control convertors processes through system bus using sources of core,RS and MPS memory.

Variant C .

Such structure is based on the separate module of computing convertor that generates results in a digital form with control actions of commutator. So as in the certain moment commutator connects only one sensor then processing will be also consecutive. So in this variant occurs loss of efficiency.

Module of computing convertor can have separate control panel or displaying unit. A keyboard provides fulfillment of several modes.

Structure A and B are simple systems of information processing, and C is more complex.

Variant D.

This structure is designed in a form of a separate remote module SOE as autonomous convertor based on specialized MPS or single-board controller.

Conclusion

As a result of proposed structures there are two main methods of construction :

1. Construction of passive subsystems processing of information as adapters of convertions  closely connected with operational devices of general-purpose microprocessor.

2. Construction of intellectual adapters or remote modules of processing system as specialized MPS or microcontrollers they are realized capturing, conversion and simple primary processing.

Notion. To improve the reliability of the structures, IPU should contain diagnostic and testing means.