Hunter Integrated Telemetry System technology
The HITS database uses CITECT SCADA software (Ci Technologies Pty Ltd). Its job is to collect, display, and disseminate the real-time data coming from the remote sites. It can also be used to graph data and generate data reports. If desired it can be used to control sites remotely, for example to initiate a water sample at a remote site by pressing a button on the HITS computer screen.
The HITS system is in the final stages of installation and testing, and is due for commissioning soon.
The hardware and software components of the system have been chosen to allow continued enhancementin order to meet future environmental, management and clients needs. This work will require a consultative process with concerned parties as the project evolves.
Currently there are approximately 50 remote sites being polled by HITS.
Site Sensors & Design Features of a HITS sites
Critical sites, where possible, use radio telemetry. Less critical sites use telephone. Some critical sites are not able to communicate with radio due to rugged terrain and so can only communicate via telephone.
The radio system is more reliable in times of natural disaster than the telephone system, which suffers from jammed exchanges and failed phone lines.
The Maitland office of the DPI Water houses the computer control systems that run the HITS system. In case of the failure of this equipment, essential components of the system can be run from other locations or even by a notebook PC in the field – until the main control system is reestablished
Site Sensor Equipment
1: Rainfall intensity
An automatic device called a ‘Tilting Bucket Rain Gauge’ (TBRG) is used to measure rainfall intensity. Rain is collected in a funnel, which drains into a measurement chamber with 0.5 mm increments.
Cumulative rainfall data across a given time period is gathered using this system.
2: Water level
Water level data is gathered using 2 methods
Active gas purge/ pressure sensor
A pressurised constant flow of gas is fed through an open-ended hose into the river to a fixed point below water level. The pressure in the hose builds up to the same pressure as the water at that depth. It is this pressure that is measured by the pressure sensor. The system relies on the principal that water depth is proportional to pressure.
As the river level rises and falls the sensor detects changes in the gas pressure inside the tube, which are then telemetered
Shaft encoder/float well
A well is built next to the river. The well is connected to the river by a buried pipe. This means that the water level in the well is the same as the river.
A shaft encoder is an instrument that detects rotation of a pulley wheel. It is mounted at the top of the well. The pulley supports a stainless steel flexible tape, which is – at one end attached to a float in the well - and at the other to a lead counter weight.
As the water level inside the well rises and falls the float does also. In turn the tape is forced around the pulley – making the pulley rotate. It is this rotation that is measured.
Salinity is a measure of the amount of salt in solution in the river. It is measured with an ‘ electrical conductivity’ sensor mounted in the river.
This sensor does not directly measure salinity but rather the ease with which an electric current flows in the water. The more salt in the water the more conductive it becomes. The measured value is temperature compensated, and displayed in unit of microSeimens/cm (µS/cm)
4: RTU (Remote telemetered unit)
This is an industrial computer which is programmed in a special language to: operate the sensors, manage communications with the control centre computers and log data onsite. It is sometimes called a Programmable Logic Controller (PLC).
5:Loggers and telephone modems
2 types: PLC (programmable logic controllers) and radio modems.
Programmable logic controller
The Programmable Logic Unit consists of a measurement and control module and a detachable wiring panel. It can store 62 000 data points. The unit has a detachable keyboard/display and can be carried to multiple stations.
This remote transceiver is a high quality, miniature, full featured, half duplex radio transceiver, designed specifically for narrow band OEM data transmission applications which employ filtered baseband or audio subcarrier data modulation.
This transceiver is a fully synthesised 5 Watt base station. It provides a single voice channel pair in either half or full duplex split frequency voice or data link applications.
Loggers with radio modems are:
- similar to RTUs except that they specialise in logging data, whereas RTUs specialise in control and communicating.
- largely interchangeable with RTUs for the HITS application.