• ru
  • en

Integrated Structural Health Monitoring Systems

The structural health monitoring system "Lel-M / A-Line 32D (DDM-M) /" based on the acoustic emission method is an uncompromising technical solution to ensure a high level of industrial safety.
Main>Products >Structural Health Monitoring systems >Integrated Structural Health Monitoring Systems

Lel-М /A-Line 32D (DDM-M)/- system of continuous structural health monitoring of hazardous industrial objects of the enterprises of oil and gas producing, oil and gas treating, petrochemical, chemical and other industries dependent on Rostekhnadzor of the Russian Federation.

It is hardwarily implemented as a distributed system of diagnostic data acquisition and processing. It incorporates the central computer station (CCS), wiring closet of galvanic isolation and power supply (WCGI), control, measuring and switching units (CMSU), concentrators and a set of digital multipurpose measuring modules in explosion-proof version (MMEPV).

Lel M/A-Line 32D (DDM-M)/, structural health monitoring system (SHM-system) is certificated for conformity to the requirements of the All-Union State Standard (GOST) R 51330.0-99 (IEC 60079-0-98), GOST R 51330.1-99 (IEC 60079-1-98), GOST R 51330.10-99 (IEC 60079-11-99), regulating the application of electrical equipment in the explosion hazard zone and is certified flameproof 1Exd[ib]IIСТ6, or 1Exd[ib]IIВТ6, or 1Exd[ib]IIАТ6.

Different variants of system configuration intended for solving a wide spectrum of problems can be implemented on the base of Lel-M /A-Line 32D (DDM-M)/.


Central computer station provides accumulation and precise analysis of all the data received, their display, decision-making and formation of operating commands for multipurpose measuring modules and the executive equipment.

Wiring closet is a device designed for power supply and galvanic isolation of concentrators and measuring lines. WCGI carries out galvanic isolation between the primary voltage 220V/50Hz and the secondary voltage of the direct current of 48V delivered to the line of cascading MMEPV, as well as optron galvanic isolation to the data transmission channel.

     Control, measuring and switching unit is designed for measurement of analog signals coming from gauges, formation of command analog signals for external executive devices and switching of measuring and executive circuits. Structurally CMSU represents a holder with the established motherboard with channel boards installed in the slots:

  • MC is a current loop measuring channel for registration of slowly varying parameters, from the primary or secondary converters equipped with a current output of 4-20 mА;
  • CC is a current loop command channel for management of various devices equipped with a command current input of 4-20 mА;
  • SC is a switching channel providing switching of external circuits by means of the relay in a controlled pattern.
Measuring line (cascading line of MMEPV) is a channel of command, management, synchronization, data transmission and power supply providing connection of multipurpose measuring units to the concentrator or WCGI.
Concentrator is an explosion-proof communication device providing securing support of several measuring lines for connection of multipurpose measuring units and equipped with high-speed digital communication channel (Ethernet) for communication with the central computing station.

    Multifunctional measuring unit is a device providing galvanic isolation of measuring channels, reception of analog signals from diagnostic and parametrical sensors, their transformation into a digital form and the subsequent processing.

  • Each unit can contain a combination of up to three blocks of measurement or formation of signals of the executive equipment command:
  • AE is a channel for registration of acoustic waves; the channel contains analog and digital frequency filters, an amplifier, an analog-digital transducer, a digital amplitude comparator, computers for calculation of characteristics of AE signals;
  • MCC is the current loop measuring channel for registration of slowly varying parameters from the primary or secondary transducers equipped with a current output of 4-20 mA;
  • CCC is the current loop command channel for command of different devices equipped with the command input of 4-20 mA;
  • PB is the power bridge channel for measurement of drift of resistance in of the resistive bridge sensor arm from the originally established rate.
Acoustic emission sensors (AES) are applied to registration of acoustic emission signals coming from plastic strain of solid media, development of defects (cracks, microcracks, delamination, corrosion, hydrogen embrittlement, etc.), friction, leak (escape of liquid and gaseous media through defects).
Pressure transducers are used for registration of values of superfluous pressure, underpressure, superfluous pressure-underpressure, absolute pressure, the difference of pressures and hydrostatic pressure (level) of liquid and gaseous, including corrosive media in the control objects under investigation.
Strain gages (resistive strain sensors) are applied to estimation of the stress-strain state of a structure and also for increase of reliability of the results of the acoustic emission control and other methods of monitoring used in TDM system.
Corrosion sensors serve for measurement of the corrosion speed by the method of electric resistance (ER) or the method of linear polarization resistance (LPR).
Vibration sensors (current output vibration velocity sensors) are intended for transformation of average mean values of vibration velocity in controllable points of the units and equipment into direct current.
Temperature sensors (resistance sensors, thermoelectric transducers) for measurement of the temperature of liquid and gaseous media.
     Temperature sensors (resistance sensors, thermoelectric transducers) for measurement of the working surface temperature of the object under control.



      Automated workplace (AWP) is a device used for remote access to the central computer station for reserve copying of the information and the unit setting. The automated workplace also is used for monitoring data processing and preparation of reports on the system operation.



Uninterruptible power supply

Weather station is a complex of measuring devices for test of temperature and air humidity, atmospheric pressure, speed and direction of the wind, presence of precipitation. It is delivered in case of need to account the influence of meteorological factors on the work of monitoring system or the object under control.


General parameters
Supply voltage for Central computer station, Communication and service device,
Intermediate station (technologic node)
Maximum number of Measuring modules in CDM system, not over
768 pcs
Maximum number of measuring channels in CDM system, not over
2304 pcs
Measuring module
Number of simultaneously used channels for measuring, control,
communication and switching
Composition of channels for measuring, control, communication and switching:
- acoustic emission channel;
- current loop measuring channel;
- current loop control channel;
- bridge measuring channel.
Data transmission type
digital self-synchronizing code
Cable type
twisted pair
Maximum cable length between adjacent Measuring modules
120 m
Galvanic isolation, not less than
500 V
Operating temperature range
-40  ÷ +60 °С
Supply voltage
48 V
Power consumption, not over
10 W
Weight, not over
5 kg
Acoustic emission channel
Operating frequency range
1÷1000 kHz (15÷500 kHz in standard version)
Gain slope:
-  analogue filter
22 dB/octave
- digital filter
60 dB/octave
Bandpass flatness
+1/-3 dB
Maximum measured amplitude of AE signal
94 dB
Accuracy of AE signal amplitude measuring
± 1 dB
Noise in the operating frequency range, not over
5 µV
Accuracy of measuring time parameters
1 µs
AE channel performance, not less than
1000 events/channe
Current loop measuring channel
Operating range
4 ÷ 20 mA
0,2 %
Current loop control channel
Operating range
0 ÷ 20 mA
Maximum load resistance
600 Ohm
0,2 %
Bridge measuring channel
Operation modes
¼  of bridge, ½  of bridge, full bridge
Minimum bridge resistance
120 Ohm
0,1 %

Main gas pipeline crossing under railways

Basic elements of a monitoring system

Module for control, measurement and commutation (MCMC)

Central computing station using satellite communication


Remote terminal


   Аcoustic emission transducer (AET)
Corrosion sensor
Cup rum-sulphat comparison electrode
   Strain gage
   Gas sensor
Sensor for electrolyte contact presence
   Temperature sensor

Acoustic emission system for the chain mount component of the skating-rink

Basic elements of a monitoring system

Multifunctional measurement module


Сentral computing station (CCS)

Meteorology station


  Аcoustic emissiontransducer (AET)