General Overview
Austdac supplied communication systems are designed to integrate with all our other communications equipment.

Austdac offers a complete network of communications, covering Longwalls, Conveyors and Roadways.

Mine Public Address Amplifier Systems
Austdac provides the amplifier audio public address systems. These are in wide use throughout the underground coal industry and also the tunnelling industry. The amplifier system is a “building block” module that readily integrates and expands to provide a full communication network.

The amplifier system is used to provide the following features:

• Provision of emergency communication even in the event of a power failure.
• Provide Pre-start alarm warnings.
• Allow Public address announcements such as emergency evacuations.
• Provide a control and monitoring and pre-start alarm system for conveyors.
• Announce Voice Message alarms.
• Connection into the mine’s telephone system thus providing a dial in and dial out facility along the amplifier system.

Main Control Unit
The Main Control unit consists of a very compact designed pcb and enclosure which controls all the latest functions available to control and monitor conveyor belts.

The main features include:

• Voice Communications along the Conveyor.
• Coverage of 6km of Conveyor and up to 8km with repeater.
• Pre-Start alarms.
• Signalling Tones.
• Surface Communications (Telephone or unique standalone station).
• Control Relays.

The range of Austdac ancillary devices allows functions on the conveyor such as emergency stop, remote isolation, sequencing of down line apparatus, and transmission of analogue signals such as vibration monitoring or temperature monitoring to be achieved using only the lanyard cable as a transmission medium.

The Austdac conveyor control system has been independently assessed to AS1755-2000 and AS4024.1 for machine guarding. The SILBUS system also has the Australian C-tick for EMC compatibility.

1. Channel Generator
There is only one channel generator per system. The heart of the operation is the channel generator. This device provides the driving signal and encodes the information from the transmitters to the receivers.

2. Remote Isolation
For remote isolation purposes each control station has two (2) switches. One switch being of the lanyard type, and the isolation switch being an on-off switch can be padlocked in the off position only. There is a transmitter inside each switch.

3. Transmitters
128 transmitter and receiver channels may be placed at various points on the cable. Multiplexing modules may increase system capacity beyond the 128 channels.

These devices are relatively simple devices and briefly operate as follows.

Each transmitter comprises a counter that is reset by the synchronising pulse. The counter then begins counting each positive edge of the waveform driven by the channel generator.

The count value is compared to the plug in code module at the front of the transmitter. Inside this code module is a binary count value encoded with diodes.

When the count value from the channel generator equals the count value from the code module, the transmitter becomes active and places a short on the two wire as soon as the signal is low and if it’s corresponding inputs are made. If its inputs are not made then it has no effect on the two wire.

4. Receivers
These are also simple devices that operate almost identically to the transmitters. They too have internal counters that compare their value to the plug in code module, but instead of placing a short on the line they have a sensing circuit that checks for the duration of the low signal. If the low signal is a wide pulse then their corresponding output is latched on and if it is a narrow pulse then the corresponding output is latched off. For a receiver to change state it must receive two consecutive signals that are the same logic. This gives a maximum data update time of approximately 300 milliseconds.

5. PullSwitches
The pullswitch provides stopping and signalling facilities for conveyors. The pullswitch is of polycarbonate construction with latching or non latching versions available.

The pullswitch utilises fully sealed gold plated microswitches and is water and dust resistant to IP65.

6. The Signal Cable
The lanyard cable has been specifically designed to meet all of the requirements of the relevant standards with particular attention given to durability and wear characteristics under the most extreme operating conditions.

The cable is designed to ensure failsafe operation of the emergency stop switches on long distance conveyor applications.

7. Belt Stations
Austdac has various belt stations available, depending upon the requirements for your conveyors. These options consist of remote isolation, interrogation button, visual indication, and telephone interface.

The belt stations are positioned along the belt at nominated distances. They are all interconnected by a pullwire cable (lanyard) and a communication cable, all of which are usually plugged and socketed.

8. Amplifier
Austdac has designed a new intelligent amplifier which is totally compatible and interchangeable with the existing unit presently used in Conveyors and Longwalls throughout NSW and Queensland.

The new amplifier has been changed with full fault diagnostics and to improve the general appearance and operation of the overall system.

The system design improvements which can be displayed on the new LCD screen are as follows:

• Local internal battery voltages level.
• Local battery charge current.
• Inbound and outbound PSA Tones to dictate cable line faults and location.
• Easy menu driven displays.
• Durable membrane.
• Volume level setting (PSA & local override).
• Optional remote headset facility.
• Noise cancelling microphone.
• Individual speaker fault indication “Left Speaker Faulty” “Right Speaker Faulty”.
• Back lit LCD display.
• Better battery life (6 months battery life left when battery is disconnected from the line).
• Lower charge current.
• Ingress protection IP66.

Learn more about this product by clicking on the brochure below:

Intrinsically Safe Conveyor Control and Monitoring System Incorporating Remote Isolation