Remote meter reading system

Flow Measurement & Control

October 2001 Flow Measurement & Control

A cost-effective, tamper-proof remote meter reading system has been developed and manufactured by a South African company, using low-cost, short-range RF transmitters. The RHM 104 system from Rotrax Technologies consists of meter transmitters, pole-mounted receiver units with RS232 interfaces and mobile handheld service readers.

By creating clusters of meters, each with its own area code, the number of cell modems required to transmit information back to a central receiving point is reduced.

Brian McElroy of Rotrax Technologies describes the system: "Pole-mounted groups of short-range meter transmitters operating on the ISM free band, with one receiver unit per group, are programmable to allow for interaction with a pre-determined receiver group and for specific information to be transmitted", he says. "Hardware and software safeguards secure against tampering or the loss of programming should power be removed".

Signals sent to receiver posts are determined by the number of pulses received from a meter reader, which indicate the allocated group address for the transmitter, the programmed serial number of the meter and the meter reading.

A damaged meter transmitter unit can be replaced by a new unit and immediately programmed via a laptop with the required identification information as well as the current reading on the meter. On the next transmission the new unit will update the receiver with the current reading, thus updating actual consumption.

When a meter transmitter is installed (whether a new installation or a replacement), it can be software triggered to transmit its data, which will immediately update the pole receiver unit as well as the handheld test unit. Handheld test receivers are used for data collection and to verify that the transmission has been sent and the data transmitted matches the meter. The handheld unit can also be used to check the range or reliable reception distance when allocating the meter transmitters to a pole receiver/area group.

Pole-mounted receivers are connected to the basestation via long-range RF modems or cellphone modems, utilising the RS232 port on the pole receiver unit. Mobile vehicles can also pick up from each area pole receiver unit and download to a vehicle-mounted laptop PC for future downloading of information at the basestation.

The software at the basestation has to be intelligent enough to realise when a system is down (or when tampering has taken place) and to report it immediately. Statistical reports can also be implemented to give trends on usage or if a 'personal' visit to the meter is required to see why no update on readings have been received for a pre-determined time, for such reasons as damaged meter or transmitter, customer away, or bypassed meter.

All RF modules are SATRA approved as well as carrying international approvals and CE mark. The RHM104 is suitable for any meter that generates a pulse, including fuel and water meters.

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Remote meter reading system

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