Selecting & Defining Command and Control Systems for Mine Ventilation Presented By: Sancar James Fredsti

Abstract:  Harsh Environment for Equipment  Communication between components is critical.  Robustness of system configuration is essential to successful design approach.  As systems age, often the configuration becomes unmanageable as equipment becomes obsolete.  Flexible design, ease of maintenance and expandability are paramount considerations.

Introduction:  Huge offering of equipment in market place overwhelms system designer with choices.  Incompatible communications methods and protocols leads to cumbersome system configuration.  Often systems created from ‘available’ components will become dysfunctional over time because of software and hardware upgrades.  Implemented on University of Nevada, Reno ventilation on demand simulator system. Which desired real time data collection, simplified operation and easily modified structure and design.

Pre Modification System  20 Manual pressure sensor points.  4 Anemometer sample points  National Inst. Analog & Digital I/O Interfaces  Regulator control through simulated stepper motor control  Fan control through analog driver, fed from remote analog speed transducer.  Centralized instrument and control points

System Description & Design Approach  Old system design approach inadequate  Need to simplify system Old System Operations Approach

Design by use of off the shelf components Design by adapting system to fit network Custom design from the ground up Design Methodologies Available

Design By Using Off The Shelf Components  Selection of components with compatible specifications is difficult.  Interfacing different manufacturers equipment is arduous and consumes system software development resources.  Communications often uses multiple protocols and layers,  Lack of definitive data and control topologies common across many manufacturers makes getting system pieces to play nicely together difficult.  Comfortable for system designer to use familiar equipment but usually results in a system that has adaptors, interfaces and translators.

Design System By Adapting To Specific Network  Selection of components with compatible communications limits the availability of hardware. No one offers everything.  Critical to select most useful communications protocol for the application and physical topology.  Keep the hardware and protocol layers similar. Mixing different protocols on the same physical layer leads to errors, failures and potential hazards.  If communications protocols require translation keep this equipment simple and close to the equipment terminus.  Be willing to break network up into manageable sections  Separate and define long haul and short haul as independent sections, this may require a mixture of hardware layer equipment.

Design System From Ground Up  More difficult to accomplish, requires hardware and software development team effort.  Ability to define hardware and interfaces specifically for the application at hand, helps eliminate forcing of hardware to work by software modification and adaptation.  Large selection of networkable controllers, processors and interface equipment.  Ability to define custom networking and interfacing of incompatible equipment.  Ability to design distributed and localized processing of collected data making system efficient and keeping network traffic to a minimum.  Easily accommodate long haul and short haul networking with custom interfaces.  Custom hardware design and building costs can be substantially less than cumbersome software development alone.

Custom Designed UNR System  Simplified system operation while expanding capabilities  Replaced manual pressure sensor system with custom designed networked 20 node dual sensor system  Replaced Interface and control cabinets with networked drivers Final Custom Network and Hardware Design

Applying Design and Selection Philosophies  Define all parameters required.  Discard approaches that require too much work  Don’t be afraid of designing new hardware  Distribute intelligence throughout the system  Communications is paramount  Use a Top Down approach, define what to do before defineng how to do it.  Keep maintenance and serviceability in mind Previous single approaches may yield disappointing results, but a mixture of design philosophies usually results in a successful final product.

Custom UNR Control System Custom designed instrument module. Note: all power, data communications and control signaling is accomplished through a single 4 conductor wire interface. This bus is shared by all modules on the network. Cluster of modules on data network. Picture shows instrument cluster. 20 Pressure Sensors, 3 Variable Speed Fans, 4 Regulators, 4 Anemometers, 5 CO2 Sensors 4 CO2 Injection points and an Outside Barometric Pressure and Dew Point instrument. Note: all power, data communications and control signaling is accomplished through a single 4 conductor wire interface. This bus is shared by all modules on the network.