Meter reading and automated wireless transmission

An explanation describing the application of Optical Direct-Reading Sensors and Wireless Intelligent Routing Technology in consumption meters, using an Automated Meter Reading System (AMR)

This article by Benny Cheung analyses the technical problems of linking existing mechanical meter systems to an AMR system based on pulses, and describes the detailed working principle, special operational modes and application of optical direct-reading (ODRS) technology and wireless intelligent routing (WIRR) technology to provide a innovative and revolutionary generation of these ODRS meters and advanced WIRR AMR systems for suppliers in energy fields.

Meters providing correct optical reading of data, using a low cost AMR system, with easy installation and no loss of data (eg pulses) is very important for operators in the energy supply industries and utilities.

Not only can they reduce operational costs but they can collect energy consumption information on time, to prevent stealing and debt and to predict and dispatch energy resource logically, allowing scientific management of the energy network.

Limited by present technology, reading and AMR of original data from meters (including IC prepaid) are mainly based on generating and accumulation of quadratic pulses to read indirectly and to transmit remotely to a management centre for processing.

The meters and AMR system based on pulse measurements have the following serious technical problems:.

1 According to international measuring rules, all measurement data of meters must be kept the same as the original data, which is shown on the figure wheel.

Readings based on pulse generation is an indirect measurement, it is involved in and intervenes in the measuring procedure, and forms a transfer of two streams of measuring data (the original wheel data and accumulated pulses) which disobey international measuring rules.

2 External environment, such as mechanical vibration, strong magnetic disturbance, water hammer phenomenon, water meter reversion, demagnetisation, meter working underwater, opening of solenoid valves and faults during transmission etc, will have a serious influence on pulse formation, accumulation and transmission which will send incorrect pulses or stop transsmission.

This will bring about an error between the data shown on the wheel and data transmitted to management centre, producing serious revenue loss and disputes with end users for operators.

3 All AMR systems used now have different technical limitations, and there is not one which can solve the following problems perfectly: remote reading with low cost and 'No Gap', readings according to requirements of timing and gradient tariff, effective steps of supervision and punishment for debt or stealing of energy.

At the same time, installation, inialization and maintenance of 'distributed' or 'centralised' AMR structure will cost too much especially replacement of any standby battery, increasing greatly the cost of operation for the operators.

As above quoted, meters and AMR systems based on pulse generating violate principle of metrology and can be seriously influenced by the external environment giving low reliability; they also bring about difficult problems of technology, cost and management during operation.

The energy market is waiting for a new solution for meters, and an AMR system which can overcome all the problems above.

Tai Feng Yuan Video Digital is experienced in knowledge and resources available in computing, automatic control, vision sensors and the measuring industry, and has developed ODRS meters using patented technology of the optic direct-reading sensor (ODRS) and used this in an advanced wireless AMR system based on wireless intelligent routing relay technology (WIRR).

ODRS meters and WIRR AMR system can be used widely in reading of meter installed in home, commercial and industrial fields: their special operation characteristics make them likely to become the next generation of meters offering AMR systems.

1 Introduction of Patent Technology of Optic Direct-reading Sensor (ODRS) Patent products.

Optic Direct-Reading Sensor (ODRS), integrates the following technologies:.

* Figure wheel counting and synchronous carry through mechanical driving.

* Optic-electrical conversion and coding of absolute position.

* Intelligent control.

An ODRS is installed on the figure wheel of any meter, independently and separately to the mechanical and electrical structure of meters.

It consists three basic parts: mechanical, opto-electrical conversion, and controlling.

Under the control of AMR system, ODRS reads the absolute position of figure wheel which stands for data, makes the optic-electrical conversion and digital coding and then transmits the data to the remote management centre.

The key technology of ODRS is exact and the corresponding 'mirror' relation between absolute position of wheel and digital codes after conversion to guarantee reading data exactly the same as that shown on the wheel.

ODRS is only powered-up at the instant of reading by the AMR system and then powered-down to improve the lifetime and reliability of the system, ensuring the with lowest power consumption.

ODRS is totally independent of the wheel; it does not have any involvement with the measuring procedure and does not disturb the operating mechanism or the measuring precision of the meters themselves.

Patented ODRS technology guarantees that the data read are exact same as shown on figure wheel.

2 ODRS Meters.

ODRS meters mean that all meters install ODRS on figure wheel independently and separately to read and transmit data to the remote management centre using the AMR system.

Meters already installed with ODRS have included ODRS electricity meter, ODRS water meter and ODRS gas meter.

3 Advanced AMR System: Wireless Intelligent Routing Relay Technology.

Thinking about reading with 'No Gap' for all meters in different installation environment (especially armoured concrete building), cost of engineering and maintenance, principle of distributed controlling and centralised management, the final choice was to use a micro-power wireless solution operated in public frequency band for AMR system for energy operators.

Wireless intelligent routing relay technology and WIRR AMR system solves all known existing problems; its special operation mode and built-in battery with high performance guarantees the system will work for 5-10 years without replacement of battery.

3.1 Principle of WIRR Technology.

WIRR means that wireless data communicate in the way of relay transmission to expand covered range and distance without increasing the transmit power.

In a wireless vector network using WIRR, according to field strength and sensitivity of each node, the node manager intelligently appoints a relay node of each planar network and a master relay node of whole network, and automatically configures an optimised route for data transfer between different relay nodes, relay node and master relay node; the node manager also automatically configures an optimised route to form a cell for data transmission within nodes in the same planar network.

Such tables are stored in the node manager.

The master relay node is responsible for data relay transfer between different relay nodes and the node manager, also for data communication between nodes in same planar network with it.

There is no fixed relay node and any node can be used as a relay node only up to field strength and sensitivity where it is placed.

When one node can not communicate with another, it will search for a suitable relay node according to routing tables to reach target node after passing the data through several relay transfer by relay nodes.

Each wireless node in the network has the function of a transceiver, operates in duplex at same frequency and has a unique address in the network.

01 to 12 are unique addresses of nodes and 99 is unique address of node manager.

Data from each wireless node is transmitted to relay node first, then transferred by relay nodes in different planar network and the master relay node to realise data relay transmission.

Wireless node is only powered-up during operation and power-down at any other time, this special mode saves power and extends the lifetime of battery to 5-10 years using optimised operation sequences.

In relation to the security and reliability of data transfer, the node manager can appoint standby node for master relay node and relay node.

When any relay node fails, node manager will transfer all job of fault node to standby relay node to guarantee reliability and security of link.

3.2 Introduction of AMR System with WIRR Technology.

AMR system with WIRR technology is made up by following units:.

* Wireless Reading Node or Wireless Reading Relay Node (WRN or WRRN).

* Local Area Node Manager (LANM).

* Wide Local Area Node Manager (WLANM).

* Handhold Reader (HHR).

* Network Management System (NMS).

WRN (or WRRN) and HHR work at frequency of 315, 433, 868 and 915MHz optionally or band of 300-1000MHz which can be programmable in steps of 250Hz with mW of transmitting level.

The flexible choice of operation frequency and low transmitting level will not have any disturbance on other equipment operated on same frequency or band and operators are not required to apply for permission.

Through standard interface RS485, RS232 or TTL (optional), WRN is connected to ODRS meters.

For ODRS electrical meter, WRN is usually powered by meter itself (internal DC+5V) or by rechargeable built-in battery which can last 48 hours when the power network fails.

For ODRS water and ODRS gas meters, WRN is powered by built-in high performance battery.

All WRNs are only powered-up at reading and powered-down after reading; A logical operating sequence and optimized routing tables keep power consumption of WRNs at the lowest level (mA) during power-up because the radio module within the WRNs uses advanced micro power IC.

All these techniques guarantee that the built-in battery can work for 5 to 10 years without replacement.

The internal clock of WRNs is synchronised to LANM.

Any WRN can be used as WRRN depending on field strength and sensitivity where it is installed in wireless network.

LANM is responsible for managing WRNs.

LANM implements operations of wake-up, reading and power-down on all its WRNs according to preset time from WLANM or orders from NMS, stores reading data into memory and transmit them remotely according to preset time of WLANM or orders from NMS; LANM can also transfer all stored data to HHR at a order from HHR.

LANM works continuously and power supplied by recharged Li battery.

Because of lowest power consumption during operation, the operator can charge battery after some operation period which will not increase cost greatly.

LNAM is synchronised with clock from NMS in real time.

WLANM is responsible for managing LANMs.

WLANM send orders of reading and upload of data on all its LANMs according to preset time or orders from NMS, stores all reading data into memory and transmit them remotely according to preset time or order from NMS through different transmission platforms; WLANM can also transfer all stored data to HHR under the order from HHR.

WLANM works continuously with power supplied by recharged Li battery.

Because of lowest power consumption during operation, the operator can charge battery after some operation period.

WLNAM is synchronised with clock from NMS in real time.

WLANM has standard external interface and wide area address; it can transmit stored data to NMS through different transmission platforms (PSTN/GPRS/CDMA/Sat c) or receive any orders of reading, controlling and inquiry from NMS remotely.

HHR is actually one removable WLANM with screen and has same functions as WALNM.

The operators can use it very easily to make initialisation during installation and fault checking for single meter during operation; the operators can also use it in such fields where there are not any known transmission platform to read data (just data stored in LANM or WLANM) of meters by manpower, bring it back to center and processed by NMS.

HHR is powered by rechargeable battery.

NMS manages all WLANMs and sends orders of reading, controlling and upload of data to WLANMs through different transmission platforms.

NMS provide sole clock for synchronisation to guarantee uniqueness of network clock and to process data it received.

The management software is mainly made up by following software modules which can be modified and developed again according to different requirements of operators: system initialisation, data collecting, tariff management, alarm supervision, statistics and analysis, system maintenance and data standby, remote controlling.

Under the cooperation with meters, NMS can cut down the allowed energy supply remotely to users who are in arrears or have tampered with the meter.

Compared with current meters and AMR system, ODRS meters and WIRR AMR system have revolutionary innovations.

They solve all existing technical problems and have bright market future and wide application in energy supplying fields.

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