The roofAlert remote monitoring system is an intrinsically safe automatic roof monitoring installation developed by Holville in conjunction with SCT. The system incorporates a data logging network that automates the collection of roof extensometer readings using the Gen4 Rock-It.

The system is based on a single pair cable that daisy chains the instruments along an excavation and relays each individual Tell Tale reading to the surface via a control box. An interface on the surface then allows for routine monitoring and Tell Tale database maintenance.

The instrument still maintains a visual read out that can be monitored manually, as it is currently used. The addition of Holville’s roofAlert module (rAMs) then allows the Tell Tale to be connected to the system and monitored remotely


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  • Cost effective (retro-fit) remote reading from surface
  • Plug and Play remote capability
  • Maintains analogue continuous visual indication as well as digital remote capabilities
  • roofAlert module recoverable from the instrument
  • Rock-It supplied with blank plate if RAM not installed
  • Remote reading communication system developed in conjunction with Holville
  • Data logging network that automates the collection of roof extensometers
  • Intrinsically Safe (IS) for use in Coal Mines (IECEx 12.0034X)
  • Single pair cable, polarity independent plug and play system
  • Daisy Chain or herring bone arrangement
  • Can be connected into existing fibre optic back bone or on an independent coms line
  • A single Local Network Controller (LNC) can connect instruments over 9km of roadway
  • Each RAM module is supplied with a declaration of conformity and  calibration results
  • Ability to monitor additional sensors/instruments i.e. strain gauges temperature, tiltmeters, accelerometers etc.
  • Future automatic logging may include such things as stress monitoring cells, instrumented bolts, shear strips, inclinometers, geophones.



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  • Routing Monitoring - MG/TG, Mains
  • Critical Infrastructure
  • Campaign Monitoring – Installation face
  • System can be supplied as comprehensive package for routine monitoring
  • System can be hired for campaign monitoring – limit capital expense
  • Integration of additional instrumentation arrays into real time monitoring network including;
      • Stress monitoring
      • Instrumented bolts
      • Load cells (cable loading or standing support loading)
      • MEMS Shear strips

 2019 roofAlert configs

For further information on the roofAlert please contact us

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