RU2485582C1 - Data collection system - Google Patents

Abstract

FIELD: information technology.

SUBSTANCE: apparatus consists of several collection units, a concentrator, an accumulator and a computer, connected to each other on a star topology by information interface lines. Each collection unit consists of a power supply, one or more data collection modules, consisting of an analogue-to-digital conversion unit, a digital signal processing unit, a control unit, a bus occupation control unit, a bus controller, a synchronisation unit, knowledge memory and a matching module. All data collection modules in one collection unit use the same interface lines (bus) to receive and transmit information and an additional bus occupation line. To provide time synchronisation of the collected data, the apparatus includes a synchronisation module which is connected to inputs of synchronisation units of all data collection modules.

EFFECT: high reliability of the apparatus, simplification thereof, high measurement accuracy, more efficient utilisation of the bandwidth of data transmission channels and broader functional capabilities.

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Description

The present invention relates to information-measuring equipment and can be used in distributed data acquisition systems generated by controlled objects, in particular in on-board measurement systems, automated process control systems, test equipment, etc.

A device is known (US patent No. 7896807, IPC A61B 5/00), which contains input converter circuits, a digital multiplexer, a local PLL generator, programming and network interface control circuits, and a network interface.

The disadvantage of this device is the multiplexing of the input analog channels, which does not simultaneously poll the channels and can lead to loss of information about the measured parameter. Also, this device does not have a mechanism for temporarily synchronizing data collection from external sources and between other similar systems.

A device is known (US patent No. 7792139, IPC H04L 12/66) containing several analog-to-digital conversion modules connected in series with each other by a twisted-pair cable. Each analog-to-digital conversion module consists of an analog-to-digital conversion unit, a digital signal processing unit, an interface controller, an Ethernet bus controller, a PLL clock recovery unit, a measurement start decoding unit. This device is the closest in fact to the proposed invention and is taken as a prototype.

The disadvantage of this device is its low reliability, since when one link of the Ethernet line is broken, some of the modules will be excluded from the information collection system. Having an internal Ethernet switch also significantly increases the complexity and cost of the device.

The objective of the invention is to increase the reliability of the device, its simplification and lower manufacturing costs, as well as increasing the reliability of the measurement, more efficient use of the bandwidth of data channels and expanding the functionality.

Figure 1 presents a diagram of a data acquisition system.

The system consists of several collection units 1, a hub 2, a drive 3 and a PC 4, interconnected according to the topology of the "star" type by information interface lines (for example, Ethernet, RS-422/485, etc.).

The collection units 1 are designed to collect data from the object of control, their processing, intermediate storage and subsequent data transfer. Each collection unit 1 consists of a power source 5, made on the basis of micromodules and / or microcircuits of secondary voltage converters, one or more data acquisition modules 6 and matching module 7, made on the basis of physical interface components with interface communication lines (specialized circuits, transformers and etc.).

Each data acquisition module 6 consists of an analog-to-digital conversion unit 8 made on the basis of analog filters and ADC chips, a digital signal processing unit 9, a control unit 10 based on microcontrollers and / or programmable logic microcircuits (FPGAs), an employment control unit bus 11, which can be made on the basis of a field (bipolar) transistor connected according to an open drain (collector) circuit, a bus controller 12, based on a microcontroller and / or programmable logic chip (FPGA), la synchronization 13, which can be executed on the basis of the counters and programmable chips generator output frequency (PLL), a memory tasks 14 executed based on flash memory chips.

Drive 3 is used for recording and long-term storage of data received and processed during data collection and can be performed on the basis of non-volatile memory (hard disks, flash drives, etc.) and a read-write controller (based on microprocessors, microcontrollers, FPGAs and etc.).

PC 4 is used for initial configuration of the system (creating tasks and controlling the process of their recording in task memory 14), displaying the results of data collection and processing (received from the collection units 1 in real time or previously stored in the drive 3) and their analysis, for which it has installed special software and mathematics (SPMO).

In order to expand the functionality of the system, several (at least two) different data collection tasks can be stored in task memory 14, one of which is selected by the digital signal processing unit 9 and the control unit 10 during operation, depending on the state of additional external task selection signals. Each task contains information that determines the operation of this module (the nomenclature of data collected by the module, the frequency of reading each of them, settings for digital filters, the structure of information packets generated by the module, etc.). The ability to store at least two different tasks in the memory of tasks 14 and the ability to change the current task using the task selection signals allows you to flexibly rebuild the system’s operating modes directly during operation, without stopping data collection, additional reprogramming operations, etc.

Temporary synchronization of all data collected by the system is carried out using a single system clock signal supplied simultaneously to the inputs of the synchronization nodes 13 of all data acquisition modules 6 in the system.

In order to expand the functionality, an additional synchronization module 15 can be introduced into the system, having a power input, an external clock input, a measurement start signal input and a system clock output connected to the inputs of the synchronization nodes 13 of all data acquisition modules 6 in the system. In the absence of an external clock signal, the synchronization module 15 independently generates a system clock signal at its output, for which purpose it has a pulse generator, which can be performed, for example, on the basis of a crystal oscillator. If there is an external clock signal, the synchronization module 15 switches the external clock signal to the output of the system clock signal by the measurement start signal. The presence in the system of a synchronization module 15 provides data collection in the absence of an external clock signal (with autonomous operation of the collection system).

The data collection system operates as follows.

After external power is supplied, the power sources 5 of each of the acquisition units 1 form the necessary set of supply voltages for the operation of the data acquisition modules 6 and the matching modules 7. Until the first pulse of the system clock signal from the synchronization module 15, the data acquisition modules 6 are in standby mode. If necessary, the operator can use the PC 4 and the SPMO installed in it to write tasks (with the replacement of previously recorded ones) to the tasks memory 14 of any of the data acquisition modules 6. Writing to the tasks memory 14 is carried out from the PC via interface lines through the hub 2, matching module 7, bus controller 12, control unit 10.

Upon the arrival of the system clock, the synchronization node 13 of each data acquisition module 6 begins the formation of a set of frequencies clocking the digital signal processing unit 9 and the control node 10. A single system clock ensures the time synchronization of all data acquisition modules 6 in the system, creating a single relative time scale.

The signals from the control object in analog form are fed to the inputs of the nodes of the analog-to-digital conversion 8, where they are pre-filtered by an analog filter in order to suppress high-frequency interference. According to the signals from the digital signal processing unit 9, the ADCs convert the analog signals into a binary digital code, which is fed to the inputs of the digital signal processing unit 9. The digital signal processing unit 9 digitally filters the data with filtering parameters obtained from the job memory 14 (digital filter order , cutoff frequency, etc.), in order to limit the frequency band of the input signal and to reduce the level of interference affecting the measurement results.

The control unit 10 selects from the data stream issued by the digital signal processing unit 9, and packs the selected data into information packets in accordance with the task programmed in the task memory 14. In addition to the actual data, each information packet includes the sequence number of the polling cycle and the current value time corresponding to the read data values. This is necessary to bring the data collected by all data collection modules 6 available in the system to a single time scale and to reliably assess the state of the monitoring object.

All data acquisition modules 6 in one data acquisition unit 1 use the same interface lines (bus) for receiving and transmitting information and a common matching module 7, which reduces the total amount of communication lines and system hardware. To avoid conflict situations (simultaneous transmission of information to the bus by several modules), an additional bus busy line is used, which has two states - busy or free, determined by the level of the electric signal on this line. Busy control unit of bus 11 of each module provides continuous reading of the status of the busy line and transmits the result to control unit 10. If the signal in the line corresponds to the “free” state and when information packets are ready for transmission, control unit 10 of one of the modules 6 through the busy control unit bus 11 sets the line to the busy state and issues an information packet to the bus controller 12, which supplements the packet with service information (module address in the system, module type, checksums, etc.), respectively favoring the received system information exchange protocol. The generated package is issued through the interface module 7 and the hub 2 to the drive 3 (for storage and subsequent analysis of the collected information) and to PC 4 (for viewing and analysis in real time). During packet transmission, the bus busy line is maintained by the node 11 in a busy state.

Upon completion of the transmission of the packet, the control unit 10 through the bus control unit 11 of the bus 11 sets the busy line to the "free" state, after which any other data acquisition module 6 can start transmitting information (if information packets are generated) 6. Thus, the most efficient use of the bandwidth information bus capabilities.

The described architecture of the data acquisition system allows moving the data collection modules 6 inside the collection blocks 1 without additional reconfiguration of the system as a whole. If one or more data collection modules 6 fails, serviceable modules continue to collect information. The introduction of the bus occupancy monitoring unit allows the use of a single information transmit-receive bus inside the collection units 1 and abandon the intra-block concentrator of information channels, which reduces the cost and weight and size characteristics of the collection units 1 and the system as a whole.

Claims (2)

1. A data acquisition system, consisting of a data acquisition module, a personal computer, nodes of analog-to-digital conversion, digital signal processing, synchronization, control, characterized in that it has several acquisition units, a hub, a drive and a personal computer, interconnected by topology of the type A “star” by the lines of the information interface, each acquisition unit consisting of a power source, one or more data acquisition modules, consisting of an analog-to-digital conversion unit, a digital signal processing unit, a control unit, and a con- the role of bus occupancy, bus controller, synchronization node, job memory, and matching module, all data acquisition modules in one data acquisition unit use the same interface lines (bus) for receiving and transmitting information and an additional bus occupancy line with two states - "busy" or "free", determined by the level of the electrical signal on this line, in addition, an additional synchronization module is introduced, which has a power input, an external clock input, a measurement start signal input and a clock signal output, Connections to the inputs nodes of synchronization acquisition modules in a data acquisition system. 2. The data acquisition system according to claim 1, characterized in that several (at least two) different data acquisition tasks can be stored in the memory of the data acquisition module tasks, one of which is selected depending on the state of additional external task selection signals.