RU175726U1 - SIGNAL SPLITTER FOR MULTI-CHANNEL ANALOG-DIGITAL CONVERTER - Google Patents

Abstract

The utility model relates to devices for converting and transmitting information and can be used in modular data collection systems for switching signals from analog signal sources for their further transmission and processing. The signal splitter for a multi-channel ADC contains an input multiplexer. The splitter is a housing in which a signal repetition circuit board with connectors for connecting analog signal sources is installed, configured to provide power to the analog signal sources from the ADC, a switching circuit board connected to the signal repetition board, the signal repetition board containing outputs in an amount corresponding to the number of the mentioned connectors and the number of ADC channels, as well as operational amplifiers connected to the connectors and connected to the outputs, while The switching plate contains a connector for connecting to the ADC. The technical result of the claimed utility model is the expansion of its functionality by providing the ability to connect a signal splitter to any type of ADC with a multiplexer at the input as part of the measuring installation while simplifying the design of the signal splitter and at the same time increasing its reliability.

Description

Technical field

This utility model relates to devices for converting and transmitting information, and can be used in modular data acquisition systems for switching signals from analog signal sources for their further transmission and processing.

Modular data collection systems are a set of tools designed to work in conjunction with a personal or industrial computer and carry out automated collection of information about the values of physical parameters at specified points of the object of study from signal sources, as well as primary processing, accumulation and transmission of data.

State of the art

The following solutions are known in the art.

Known computer diagnostic USB-box, performing the function of a multi-channel data acquisition system and designed to transmit a signal from an analog sensor to a computer during computer diagnostics in the data acquisition system. The input of this set-top box is made with the possibility of connecting it to sensors with an analog output signal, including a capacitive sensor, an inductive sensor and a probe-voltage-divider type sensor, and the output is capable of connecting a personal computer to the USB-2.0 input port, preferably in the form of a portable a laptop computer, and equipped with test software that is used to detect malfunctions of diagnosed systems. The set-top box provides the branching and analog-to-digital signal conversion function, the latter being carried out by a microcircuit with a bit size of at least 12, and the set-top box’s operation as a whole is controlled by a microprocessor installed in the line connecting the ADC output to the PC and made in the form of a microcircuit with an integrated interface USB, the output of which is connected to the USB input port of a PC. In the line between the sensors and the ADC, a surge protection device and a voltage follower are installed in series, the microprocessor is equipped with a reprogrammable memory device. The ADC, the microprocessor with a reprogrammable memory device, the voltage regulator, the overvoltage protection device and the voltage follower are mounted on a common circuit board, placed in a common housing and taken together form a computer diagnostic USB-box. The ADC and the microprocessor are connected via a voltage stabilizer to the output terminals of the voltage, preferably 5 V, located in the USB input port of a personal computer and connected to the output of the built-in power supply of the specified computer (RU 99075, publication date 10.11.2010).

A disadvantage of the known device is that the design of the USB set-top box, which simultaneously performs the function of splitting the analog signal and transmitting it from the analog sensor to the computer via the ADC, already contains a built-in ADC, which leads to a limitation of user capabilities due to the inability to replace and use another type of ADC, in case of its breakdown or due to user preferences. In addition, this device assumes the presence of only three channels, does not provide sensors with power, and does not provide convenient disconnection and connection of sensors, which is dictated by the features of using this device for a fairly narrow class of problems: diagnostics of internal combustion engines.

Known measuring node of a non-contact non-pipe diagnostics of underground pipelines, which performs the function of processing and branching the signal and is designed to be connected to six sensors that continuously measure the components of an alternating magnetic field, which receive information about the technical condition of pipelines. The measuring unit contains six selective amplifiers, to which the sensors are connected, at least six relay modules, connected on the one hand to the ADC, and on the other hand through the interaction channels, to the receiving modules, the outputs of which are connected to the output driver, which in its queue, through a USB port connected to a personal computer. The power source is a battery (RU 2504762, publication date 01/20/2014).

The disadvantages of the known measuring node are that it is an integral part of the diagnostic device related to the data acquisition system, which makes it impossible to change the elements of such a device, i.e. the impossibility of connecting a separate node with the function of a branched signal to the device and replacing its elements if necessary. So, for example, in this device, all incoming signals pass through amplifying stages without fail, which is not always necessary when organizing data collection. Also in this composite device there is no possibility of replacing the ADC module, since the splitter, repeater and ADC module are made in one product.

A device for collecting data, processing a signal and storing the obtained measurement results, performing the function of branching the signals of the analog sensors by means of a node containing one or more inputs for receiving analog signals from the sensors connected to the processing unit containing the analog signal current amplifier, filter, ADC as well as through the presence of a digital signal processor for processing, a programmable logic integrated circuit (FPGA), a microprocessor unit, including internal memory with an external real-time operating system and an interface for connecting a control computer. The device contains a built-in or external power supply unit that provides power to the sensors. An analog signal that determines, for example, the level of noise, vibration, temperature, pressure, is fed to the input of a data acquisition device containing a node with the function of a signal splitter, by means of a sensor, and then amplified by passing through a signal amplifier by current, it is filtered and fed to the ADC input where it is converted to a digital signal. A digital signal is input to the processor for processing, recording, and analysis (KR 20040034316, publication date April 28, 2004).

The disadvantages of this device is that the node of the signal splitter is made integrated in the data acquisition device, which does not provide the ability to quickly replace the ADC and the elements of the data acquisition device when such a need arises.

The closest analogue to the claimed solution is an analog signal converter containing electronic switches connected to capacitors, which are connected on one side to inputs intended for connecting analog signal sources, and on the other hand, with a connecting element. The connecting element is connected to the output of the device through an operational amplifier. Such a module can operate in a multiplexer-repeater or repeater-converter mode. Moreover, the operating modes of this device can be switched by a control signal. (US 4,546,324, 10/08/1985).

This device can perform the same function of branching-repeating the signal as the claimed device. A disadvantage of the known device is the excessive complexity of its design. Also, this device does not involve removing power from the ADC to analog sensors, which limits the scope of the device when building portable data acquisition systems.

Utility Model Disclosure

The claimed technical solution is aimed at the use in mobile, portable data collection systems, which may have different equipment depending on the tasks in the research. In this regard, the objective of the utility model is to create a compact, reliable signal splitter that allows you to connect it to the elements of the data acquisition system (measuring units) at any place where they are located, and provides the ability to choose the types of analog signal sources, the order of their connection, change elements installations, in particular, providing the possibility of choosing the type of ADC depending on the need or preferences of a particular user, as well as providing convenience in the implementation installation in case of failure and the need for quick and easy replacement of device elements.

The technical result of the claimed utility model is the expansion of its functionality by providing the ability to connect a signal splitter to any type of ADC with a multiplexer at the input as part of the measuring installation while simplifying the design of the signal splitter and at the same time increasing its reliability.

The problem of the utility model is solved by performing a signal splitter for a multi-channel ADC containing a multiplexer at the input, which is a housing in which a signal repetition circuit board with connectors for connecting analog signal sources is installed, configured to provide power to the analog signal sources from the ADC, printed a switching board connected to the signal repetition board, wherein the signal repetition board contains outputs in an amount corresponding to the number of mentioned connectors and the number of ADC channels, as well as operational amplifiers operating in repeater mode, connected to the connectors and connected to the outputs, while the switching board contains a connector for connecting to the ADC.

The claimed design of the device provides for the branching of the incoming analog signal and its repetition in a single module while providing the sources of the analog signal with power, which ensures the compactness of the device and the possibility of its use as a removable module in any data acquisition systems. A data acquisition system, including a splitter of the claimed design, can operate from a laptop PC (eg laptop) without the need for additional power.

The ADC is not included in the design of the claimed device, but is connected to it from the outside due to the connector on the switching board for the ADC, which makes it possible to connect the device to any type of ADC, depending on the tasks and user preferences, while simplifying the design.

Sources of the analog signal are not built into the device design, but are connected to it externally due to the presence of connectors on the signal repetition board, which makes it possible to use any necessary signal sources (for example, sensors and / or pulse shapers, for example, electric stimulators, and / or amplifiers connected, for example, with electrodes), depending on the tasks and preferences of the user. Due to the absence of built-in analog signal sources in the splitter design, the dimensions are reduced and the design is simplified. The splitter is configured to power analog signal sources from the ADC, due to which the device can operate from a laptop PC without the need for an additional power supply in the design.

Due to the presence on the board of the signal repetition of operational amplifiers connected to the connectors of the board and connected to its outputs, it is possible to pass an analog signal from signal sources to an ADC with a multiplexer at the input with the exception of the inter-channel transmission of an analog signal to an ADC, which ensures the reliability of the measurements obtained. Due to the placement in the case of the switching board connected to the signal repetition board, the splitter is resistant to mechanical stresses, which further increases the reliability of the design.

Due to the execution of the signal repetition of the outputs in an amount corresponding to the number of its connectors and simultaneously corresponding to the number of ADC channels, the branching of analog signals is provided when they pass from each signal source to the ADC with an input multiplexer and the ability to quickly assemble and disassemble the data acquisition system while simplifying splitter designs.

Thus, due to the placement of a signal repetition board and a commutation board in the splitter housing, made with the possibility of connecting to each other, as well as due to the presence of connectors for analog signal sources in the housing and on the signal repetition board and connector for connecting to the ADC in the housing and on the switching board, expansion of its functionality is achieved, in particular, it is possible to connect to the splitter any analog signal sources and any type of ADC with input multiplexer, fast and simple replacement and reconnection of signal sources and ADCs while simplifying the design, thereby simplifying the design of the splitter, and when using the claimed splitter, the user does not need to solder parts to the device, or use unreliable screw terminals to connect the required signal sources or another ADC model . The claimed device is reliable in operation, since it eliminates the inter-channel signal passage of an ADC having an input multiplexer, there is no risk of mutual signal pickups from several analog signal sources used simultaneously.

In the particular case of the implementation of the utility model, sensors (pressure and / or force, and / or the angle of rotation of the object, and / or electric potential, and / or temperature, and / or fluid flow rate) and / or electrical stimulators are used as sources of the analog signal and / or electrical stimulators and / or bioelectrodes.

The signal repetition printed circuit board can be installed vertically oriented in the housing, which makes it possible to compactly position it in the housing and output connectors for analog signal sources to the upper panel of the housing. With this arrangement of connectors, the load when connecting / disconnecting analog signal sources is applied vertically, which eliminates mechanical damage to the connectors - a fairly common reason for the failure of such devices.

Three-core connectors (for an analog signal from a source, power supply and common ground) of the 6.25 mm TRS type (Jack jack, for example, the ST-020 stereo model) can be used on the signal repetition board, which makes it possible to quickly and conveniently assemble measuring installation as part of a data acquisition system.

An additional signal repetition board connected to the switching board can be installed in the device case. In this case, two signal repetition printed circuit boards can be installed vertically in the case in the case one after the other, which allows convenient operation due to the compact arrangement of the boards in the case and the removal of connectors for analog signal sources on the top panel of the case.

On the switching board, the DB-37M connector can be used to connect the LCARD E-154 model ADC or another 8-channel ADC, or the DB-15M connector can be used to connect the LCARD E-14140 model ADC or another 4-channel ADC.

The switching board can preferably be located in the case horizontally oriented with the output of the connector for connecting to the ADC on the front panel of the case, which provides convenience when operating the device in conjunction with any types of ADCs, including industrial ones.

The housing of the signal splitter for multi-channel ADCs can preferably be made in the form of a horizontally oriented parallelepiped. On the top panel of the case in one row are made holes for the connectors of the signal repetition board, designed to connect analog signal sources. A hole for the ADC connector is made on the front panel of the case. With this embodiment, the housing of the signal splitter with the specified location of the holes for the output of the connectors provides the possibility of compact placement of printed circuit boards in it, which leads to a decrease in the dimensions of the housing and, accordingly, the entire device of the signal splitter as a whole. The specified execution of the housing ensures the stability of the device to mechanical stresses that may occur during its operation, increases its durability.

Description of drawings

The claimed utility model is illustrated by drawings, which depict the following:

in FIG. 1 - General view of the design of the splitter assembly;

in FIG. 2 - a circuit board for repeating a signal and a switching board connected to each other;

in FIG. 3 is a diagram of an arrangement of connectors on a signal repetition board;

in FIG. 4 is a layout diagram of connectors on a switching board.

The positions in the drawings indicate the following elements:

1 - splitter housing;

2 - printed circuit board signal repetition;

3 - connectors of the signal repetition circuit board for connecting analog signal sources;

4 - printed circuit board;

5 - connector printed circuit board for connection to the ADC;

6 - operational amplifiers;

7 - outputs of the circuit board signal repetition;

8 - resistance of the switching board;

9 - connectors of the switching board for connecting signal repetition;

The signal splitter for a multi-channel ADC, containing an input multiplexer, consists of a housing (1), in which a signal repetition board (2) is installed with connectors (3) located in a row on the upper wall of the housing (1), for connecting analog signal sources ( which are used as sensors and / or electrical stimulators and / or bioelectrodes), and a switching board (4) connected to the signal repetition board (2), with a connector (5) on the front panel of the housing (1) for connecting to the ADC (Fig. one).

The signal repetition board (2) contains, for example, four input connectors (3), the number of which corresponds to the number of ADC channels, as well as operational amplifiers (6) connected to the connectors (3) and connected to the outputs (7), and the switching board ( 4) contains a series of resistances (8) and a connector (5) for connecting to the ADC (see Fig. 2). The ADC is connected directly to the front panel or through a connecting wire.

The signal repetition board (2) contains a number of connectors (3) located on the upper wall of the housing (1), and connectors (7) for connecting the switching board through the connecting wires located in the housing (see Fig. 3).

A connector (5) for connecting the ADC and connectors (9) for connecting the signal repetition board through the connecting wires located in the housing are fixed on the switching board (4) (see Fig. 4).

In the particular case of the implementation of the utility model, several signal repetition boards (2) can be installed in the splitter case, for example, two boards (2), the connectors (3) of which are arranged in two rows on the upper wall of the case (1) (see Fig. 1 )

Utility Model Implementation

A signal splitter for a multi-channel ADC containing an input multiplexer is made by assembling printed circuit boards with their subsequent installation in the housing.

Printed circuit boards can be made on PCB with a thickness of at least 1.5 mm with a double-sided copper coating of at least 18 microns, which are milled and drilled according to the drawings, and then etched on the track and surface mounted according to the circuit diagram (see Fig. 2 ) In the boards, metallized holes are made for the connectors, which are mounted in the holes through installation. To assemble the device, a plastic case “Gainta G706” can be used with front and rear panels made of PCB using the same technology as printed circuit boards.

For switching boards, single-row 2.54 mm pin connectors can be used. To implement the repetition, the TL074 integrated circuit or its analogues are used. The circuit uses 1% accuracy chip resistors in the 0805 package and X7R chip capacitors 10% accuracy at 50 V (ratings are shown in Fig. 2).

In a particular case, the claimed device is used to register biopotentials in the laboratory, when the researcher has a limited number of devices, and the experiment requires different approaches to data collection.

The device operates as follows.

From bioelectrodes (analog signal sources), the signal is fed to a multi-channel amplifier, from which data is fed to the splitter channels (through connectors for analog signal sources on the signal repetition board) connected to an 8-channel ADC with a certain digitizing frequency. At the same time, there is also a 4-channel ADC with a higher sampling rate. To conduct a similar experiment with a higher sampling frequency, but with a smaller number of channels, the splitter is connected to another ADC without disassembling the installation, and the first 4 channels are recorded with a high frequency, then the wires in the splitter sockets are changed and the next 4 channels are registered.

The device allows you to measure the biopotentials resulting from the induced electrical stimulus and track signals and stimuli simultaneously on a PC monitor. In this case, a wire from an electrical stimulator (an analog signal source) is inserted into one of the switching channels (into the connector for connecting an analog signal source), and the rest of the installation remains assembled, while the inter-channel transmission of the signal from the stimulator to the splitter channels is excluded by the design of the claimed splitter.

On the screen of an electronic recorder, you can observe data from bioelectrodes and a stimulator signal at the same time. If it is necessary to register the force of muscle contraction in response to stimulation and the biopotential arising at that time in the muscle, the force sensor is switched on in one of the sockets (in the connector for connecting an analog signal source), and it receives power from the ADC, giving a signal amplified by current to the ADC channel. Thus, it is possible to track signals from the electrode (characterizing the biopotential of the muscle, the strength of its contraction) and observe the stimulating signal on the screen of the electronic recorder.

Prototypes of the inventive signal splitter for a multi-channel analog-to-digital converter containing an input multiplexer with a number of channels from 4 to 8 were made. The signal splitters had the following technical characteristics.

The current signal was amplified by means of the operational amplifier U1D.

The input for connecting an external source of analog signal on a printed circuit board was made by the corresponding Jack connectors of 6.25 mm into three wires for the signal from the source, power and ground. The number of connectors is from 4 to 8.

Bandwidth (frequencies): 0 (direct current) - 100 kHz.

The power supply (when powered by USB 2.0) was not more than 300 mA in total for all channels. This parameter was determined by the power source and the type of ADC. When powering the ADC via USB, this parameter is 500 mA minus the consumption of the ADC itself.

Dimensions of the device case: 140 × 110 × 35 mm. Printed circuit boards had dimensions: 53 × 14 mm (switching board) and 134 × 20 (repeating board).

Noise: no more than 10 μV in the entire passband.

The systematic error in signal repetition was not more than 1% for sources with an output resistance of not more than 300 Ohms (U _out = U _in ⋅ R _in / (R _in + R _ps )). Operating temperature: 0-50 ° C.

The working range of input voltages is from -3.5 V to +3.5 V.

The input current for the operating voltage range is not more than 0.12 mA.

Input impedance - 30 kOhm.

Compatible with ADC. For the eight-channel version, full compatibility with the L-CARD E154 was provided. Through the connecting wire, the device provided compatibility with any ADC having a range of permissible input voltages from -5 V to +5 V and an input resistance of at least 10 kOhm.

The data collection system in the particular case consisted of the following devices: LCard E154 ADC, 8-channel repeater repeater, a set of shielded wires for signal transmission with tinned ends, a calibrated signal generator with a 6.3 mm Jack connector for channel testing, PowerGraf software HL (manufactured by DISoft).

The claimed signal splitter for a multi-channel ADC containing an input multiplexer provided simplification of switching of analog signal sources, mobility and convenience in the research process by obtaining a compact and easy-to-configure data collection system that works, including from the laptop. In addition, the inventive device also eliminates the inter-channel signal passage at the ADC.

Claims (7)

1. A signal splitter for a multi-channel ADC, comprising an input multiplexer, characterized in that it is a housing in which a signal repetition circuit board with connectors for connecting analog signal sources is installed, configured to provide power to the analog signal sources from the ADC, a printed circuit board switching connected to the signal repetition board, and the signal repetition board contains outputs in an amount corresponding to the number of said connectors and the number of channels All ADCs, as well as operational amplifiers connected to the connectors and connected to the outputs, while the switching board contains a connector for connecting to the ADC. 2. The signal splitter according to claim 1, characterized in that sensors and / or electrostimulators and / or electrodes are used as sources of the analog signal. 3. The signal splitter according to claim 2, characterized in that pressure sensors and / or force and / or angle of rotation of the object and / or electric potential and / or temperature and / or flow velocity are used as sources of the analog signal. liquids. 4. The signal splitter according to claim 1, characterized in that the signal repetition printed circuit board is mounted vertically oriented in the housing. 5. The signal splitter according to claim 4, characterized in that the connectors of the TRS type 6.25 mm are used as connectors on the signal repetition board. 6. The signal splitter according to claim 1, characterized in that the switching board is horizontally oriented in the housing with the placement of the connector for connecting to the ADC on the front panel of the housing. 7. The signal splitter according to claim 6, characterized in that the DB-37M connector for connecting the LCARD model E-154 or the DB-15M connector for connecting the LCARD E-14140 model ADC is used as a connector for connecting the ADC on the switching board.

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