Data collection system on module E14-140 for testing a single-stage compressor unitfor external characteristics at high and medium discharge pressureA. A. Val’ke, R. Yu. Goshlya, and S. S. Busarov

Citation: AIP Conference Proceedings 1876, 020093 (2017); doi: 10.1063/1.4998913View online: http://dx.doi.org/10.1063/1.4998913View Table of Contents: http://aip.scitation.org/toc/apc/1876/1Published by the American Institute of Physics

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Data Collection System on Module e14-140 for Testing a Single-stage Compressor Unit for External Characteristics

at High and Medium Discharge Pressure

A.A. Val'ke1, R.Yu. Goshlya1, a), and S.S. Busarov1

1Omsk State Technical University, pr. Mira 11, Omsk, 644050, Russian Federation

a)lab_r@list.ru

Abstract. The article describes the system for collecting, processing and transmitting data from the experimental stand for testing a prototype of a single-stage compressor unit for external characteristics at high and medium discharge pressures, based on module E14-140M. The composition, purpose and main characteristics of the system are presented in the paper. Attention is paid to the parameters and capabilities of the E14-140M module made by Russian company L-CARD. The user interface of the data collection system is given.

Keywords: data collection system, cryogenic technology, automation.

INTRODUCTION

While analyzing the processes taking place in compressor stages, a number of physical parameters, such as pressure, temperature, gas flow, piston displacement in the cylinder, and cycle time should be monitored. For these purposes, an automated data collection system was developed. It is based on a data card (type E14-140M) manufactured by L-CARD.

STATEMENT OF THE PROBLEM

The system for data collection and transmission of the experimental stand for testing the compressor unit by external characteristics at high and medium discharge pressures should monitor the following parameters: - the change of the current temperature in the cylinder of the compressor stage during the operating cycle; - the change of the current pressure in the cylinder of the compressor stage during the operating cycle; - the control of the current position of the compressor stage piston during the operating cycle; - the inlet cylinder gas temperature; - the outlet cylinder gas temperature; - measurement of the operating time of a single-stage compressor unit. The range of controlled parameters involves: - the pressure is from 0.1 MPa to 150.0 MPa; - the temperature is from 20° С to 180° С; - the cycle time is from 0.01 s to 60 s.; - the control of the compressor unit power consumption is from 0 to 10 kW; - the gas flow rate is from 200 cm3 / min; - the range of the controlled piston micro-movements is from 0.01 to 200.0 mm;

Oil and Gas Engineering (OGE-2017)AIP Conf. Proc. 1876, 020093-1–020093-6; doi: 10.1063/1.4998913

Published by AIP Publishing. 978-0-7354-1556-0/$30.00

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The accuracy of the temperature measurement is ± 0.1 ° C. The accuracy of the pressure measurement is ± 1.0 kPa. The length of the control zone is made by a resistive position sensor from 0.5 to 205 mm. The accuracy of determining the position of the piston is± 0.05 mm.

THEORY

Module E14-140 made by Russian company L-CARD is designed for developing various data collection systems. The connection to the personal computer and the power supply of the module is via the USB. The main characteristics of the E 14-140 module are presented in Table 1 [1].

Table 1. characteristics of the E 14-140.

ADC Number of channels 16 differential or 32 single-ended ADC resolution 14 bit Effective bit capacity 13.3 bit (100 kHz, scale range 2.5 V) Input resistance (with single-channel input) Not less than 10 МОhm Input signal measuring ranges ±10 V; ±2.5 V ; ±0.6 V; ±0.15 V Maximum conversion frequency 200 kHz (for internal or external hardware synchronization) Synchronization From external synchronization signal, analog signal-level,

internal. Multi-module synchronization is possible Input protection ± 30 V (power on)

± 10 V (power off and in suspend mode) Microcontroller type AT91SAM7S256 Clock frequency 48 МHz Internal data RAM 64 КB Internal EPROM programs 256 КB DAC (option) Number of channels 2 Bit depth 16 bit DAC Setting Time 0.7 ms DAC operation mode Synchronous, asynchronous Maximum frequency of data output 200 KHz Output range ±5 V Output current, no more than ±10 mА Digital inputs and outputs Number of outputs 16 parallel, asynchronous with common resolution outputs Number of inputs 16 parallel, asynchronous Synchronization inputs and outputs Input interrupt controller, ADC input / output Type of logic CMOS/TTL Power from USB bus Consumption current

Up to 240 ma (in active mode without DAC), Up to 380 ma (in active mode with DAC)

Outputs for supplying external circuits +5 V, up to 100 ma, ± 15 V, up to 20 ma for each of the circuits (option)

Dimensions — 129x95x26 mm As can be seen from the characteristics, this module provides an analog-to-digital conversion frequency of up to

200 kHz, which is sufficient for solving most data collection tasks. Besides, there is a possibility to select the necessary signal amplification factor, which allows using different types of sensors in one system. Figure 1 shows the block diagram of the module [2].

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FIGURE 1. Block diagram of module 14-140M.

The E14-140-M architecture provides independent control of three objects: ADC, DAC and digital I / O. In particular, the independence of the frequencies of ADC and DAC in synchronous mode is realized. The I / O of these control objects can be independently started or stopped. Both synchronous and asynchronous (single-shot) modes are possible, both ADC and DAC.

Functional scheme E14-140-M consists of: - ARM-controller type AT91SAM7S2568 providing internal control of the module and support for the USB interface, as well as debugging interface JTAG. - A switch for switching signals from analog inputs to the amplifier input. - An amplifier having 4 levels of gain. - 14-bit LTC1416 serial-to-digital converter. - ADC buffer storing one 14-bit ADC readout in 8 + 8 bit format with extended additional code mark. - FPGA , carrying out internal control logic. - EEPROM of 1 KB of type M95080, necessary for storing calibration coefficients. - Two-channel 16-bit DAC. - Digital inputs and outputs registers. - A quartz oscillator for synchronizing the FPGA.

The entire periphery of the controller, related to the collection / output of data (ADC, DAC, digital I / O and timing) is connected to the ARM controller via the FPGA. In its function, the FPGA acts as a slave device (relative to the ARM-controller), which matches the logic of the peripheral ports of the ARM-controller with the data collection and output nodes.

The module has a voltage converter ± 15 V not presented in the figure. It is intended for supplying the analog input nodes of the module. The source has a smooth start when turned on, current protection and can be turned off in low power mode. The power outputs are located on the DIGITAL connector. The operation conditions of of the analog path modes device, the ADC measurement ranges, the number of polled channels and their polling sequence, the synchronization type and source, the ADC clock source, and the conversion frequency are software configurable. The module is included in the State Register of Measuring Instruments SI No. 019016.

EXPERIMENTAL RESULTS

The system software is developed in Borland C ++ Builder. The software consists of the following subprograms: - data receiving and processing subroutine; - data display subroutine; - software configuration subroutine; - archive subroutine.

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The data receiving and processing subroutine is designed to read information from module E14-140M. The basis of this subroutine is the module E14-140M-oriented functions. These functions are developed for the operating systems of the WINOWS family lusbapi.dll. The library is developed by L-CARD company and is free. The data display subprogram displays the change of the monitors compressor stage parameters in real time. The data display window is shown in Figure 2. The frequency of the data updating on the screen is 1 Hz.

FIGURE 2. Data display window.

Subroutine setup software allows us to specify parameters of the survey module E14-140M. The preferences

window is shown in Figure 3.

FIGURE 3. Parameters settings window.

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In the software configuration subroutine, the following parameters are set: • Clock pulses. The clock source is internal or external. • Stream of clock pulses. Allow or prevent the stream of clock pulses. • Synchronization mode. The value of this field can specify different types of synchronization of data input from the ADC. • Number of channels. The number of active channels from which information is received. • The frequency of the ADC. • Frame delay. • Frame frequency. • The number of the physical channel. Sets affinity of the logical channel displayed on the screen and the physical channel is connected to a particular sensor • Range. The input voltage range for the current channel is set. • Title. The name of the current logical channel. • Scale factor. Scaling factor of the current logical channel. • Differential pair. Sensor connection mode (differential or common ground). • Display. Output the current logical channel to the screen or not. • Reading. To receive data from the current logical channel or not. The archive operation subroutine is intended for data storing, as well as for its subsequent processing and display.

DISCUSSION OF THE RESULTS

The system is designed to obtain experimental data on the instantaneous operating process parameters of the slow-speed quasi-isothermal stage, the system allows to display the obtained data in the form of graphs on the screen of a personal computer and an array of data in txt format, which subsequently greatly simplifies the export of experimental data. The obtained results of the experimental studies using the data collection and transmission system are presented in [3, 4].

CONCLUSION

The system of data collection and transmission of the experimental stand for testing the compressor unit by external characteristics at high and medium discharge pressures makes it possible to obtain experimental data on the processes taking place in the compressor stage for the purpose of subsequent analysis and comparison of the characteristics of compressor stages of different types and manufacturers. The obtained experimental data make it possible to determine the processes of heat exchange and the velocity of gas movement during the working cycle in the future.

ACKNOWLEDGMENTS

Applied scientific research and experimental development are carried out with the financial support of the state represented by the Ministry of Education and Science of Russia. Unique identifier of applied scientific research RFMEFI57715X0203.

REFERENCES

1. Data collector E14-140. Passport 4221-008-42885515 PS. 2. Module E14-140 i E14-140M. Service manual. 3. AT91SAM7S Series Summary/Datasheets 26175BS–ATARM–04-Nov-05// Available at:

http://www.farnell.com/datasheets/9377.pdf 4. John D. Lenk, Handbook of Practical electronic circui, (Prentice-Hall, Ink., Englewood Cliffs, 198).

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5. V. L. Yusha, S. S. Busarov, R. Yu. Goshlya, А. V. Nedovenchanyi, B. S. Sazhin, М. А. Chizhikov, and I. S. Busarov, International Conference on Oil and Gas Engineering, OGE-2016, 297-302 (2016).

6. S. S. Busarov, A. V.Nedovenchanyi, A. Yu. Gromov, R. Yu.Goshlya, and I. S. Busarov, International Conference on Oil and Gas Engineering, OGE-2016, 281-287 (2016).

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