690
Basing on the above rules, a creation of a communication system made of a sensor network in which routing is based on a swarm algorithm was suggested by KOMAG. Each data
frame transferred by the Measure Transmission Unit (MTU) is marked by a quality coefficient WP specifying the transmission priority referring to the effectiveness of data transmission to the main transceiver stations. This coefficient can take a value that conforms to one
of connections or path metrics (Feeney 2009).
2.3 Distributed control system
A distributed control system (DCS) is a specially designed automated control system that
consists of geographically distributed control elements over the plant or control area. It differs from the centralized control system wherein a single controller at a central location handles the control function, but in DCS each process element or machine or group of machines
is controlled by a dedicated controller. DCS consists of a large number of local controllers in
various sections of plant control area which are connected via a high speed communication
network. R&D projects, realized at KOMAG, enabled a development of distributed control system modules under the trade name KOGASTER. KOGASTER is a good example
of a system which is able to include and unite, mentioned above, self-powered sensors and
wired/wireless computer communication networks, and is implemented in a harsh mining
environment.
The KOGASTER control and diagnostic system is a distributed system using CAN bus
and CANopen protocol (Bartoszek et al. 2013, Bartoszek et al. 2014), for communication.
It is used for local control in mining machines and equipment (Jura et al. 2015, Jura &
Bartoszek 2017). Use of CAN bus and CANopen protocol causes that it is an open system.
The characteristic features of the KOGASTER control system are as follows:
− distributed structure,
− intrinsically safe, redundant CAN bus,
− intrinsically safe manufacture of system modules.
2.3.1 Structure of distributed control system
The structure of the distributed control system consists of control modules, inputs-outputs,
measuring transducers, actuating components and digital interface, connected with digital
CAN bus. The possibility of power supply and data transmission in one bundle of wires is
an advantage of this solution.
The reliability of distributed system is achieved by the redundancy of CAN bus and doubling the modules and transducers, which increases unit manufacture cost but enables to
decrease costs resulting from possible breakdowns caused by machine failure. A battery powered locomotive equipped with two independent control panels and two drives is a good
example.
2.4 Systems for measuring the operational parameters of roof support
On the market there are measuring systems enabling measurements of roof support selected
parameters. The systems have different functionalities. They differ in technical solutions as
regards data transfer method and feeding systems. An analysis of the existing solutions indicates that wire and wireless systems for measuring the pressure in legs are available. Pressure
measurements are used for a control of roof support load-bearing capacity as well as for
a verification of proper roof support selection to in-situ mining conditions (Płonka et al.
2017). In the scope of roof support geometry measurements wire systems are available.
2.4.1 Concept of measuring system
At present a progress in the field of automation of longwall systems does not include monitoring of roof behaviour and preventing against disadvantageous phenomena associated
with roof behaviour, such as roof falls to the longwall face or lack of roof fall behind the
Basing on the above rules, a creation of a communication system made of a sensor network in which routing is based on a swarm algorithm was suggested by KOMAG. Each data
frame transferred by the Measure Transmission Unit (MTU) is marked by a quality coefficient WP specifying the transmission priority referring to the effectiveness of data transmission to the main transceiver stations. This coefficient can take a value that conforms to one
of connections or path metrics (Feeney 2009).
2.3 Distributed control system
A distributed control system (DCS) is a specially designed automated control system that
consists of geographically distributed control elements over the plant or control area. It differs from the centralized control system wherein a single controller at a central location handles the control function, but in DCS each process element or machine or group of machines
is controlled by a dedicated controller. DCS consists of a large number of local controllers in
various sections of plant control area which are connected via a high speed communication
network. R&D projects, realized at KOMAG, enabled a development of distributed control system modules under the trade name KOGASTER. KOGASTER is a good example
of a system which is able to include and unite, mentioned above, self-powered sensors and
wired/wireless computer communication networks, and is implemented in a harsh mining
environment.
The KOGASTER control and diagnostic system is a distributed system using CAN bus
and CANopen protocol (Bartoszek et al. 2013, Bartoszek et al. 2014), for communication.
It is used for local control in mining machines and equipment (Jura et al. 2015, Jura &
Bartoszek 2017). Use of CAN bus and CANopen protocol causes that it is an open system.
The characteristic features of the KOGASTER control system are as follows:
− distributed structure,
− intrinsically safe, redundant CAN bus,
− intrinsically safe manufacture of system modules.
2.3.1 Structure of distributed control system
The structure of the distributed control system consists of control modules, inputs-outputs,
measuring transducers, actuating components and digital interface, connected with digital
CAN bus. The possibility of power supply and data transmission in one bundle of wires is
an advantage of this solution.
The reliability of distributed system is achieved by the redundancy of CAN bus and doubling the modules and transducers, which increases unit manufacture cost but enables to
decrease costs resulting from possible breakdowns caused by machine failure. A battery powered locomotive equipped with two independent control panels and two drives is a good
example.
2.4 Systems for measuring the operational parameters of roof support
On the market there are measuring systems enabling measurements of roof support selected
parameters. The systems have different functionalities. They differ in technical solutions as
regards data transfer method and feeding systems. An analysis of the existing solutions indicates that wire and wireless systems for measuring the pressure in legs are available. Pressure
measurements are used for a control of roof support load-bearing capacity as well as for
a verification of proper roof support selection to in-situ mining conditions (Płonka et al.
2017). In the scope of roof support geometry measurements wire systems are available.
2.4.1 Concept of measuring system
At present a progress in the field of automation of longwall systems does not include monitoring of roof behaviour and preventing against disadvantageous phenomena associated
with roof behaviour, such as roof falls to the longwall face or lack of roof fall behind the