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НаименованиеMonitoring gas control points

 

The requirements to prevent emergencies when storing and delivering gas and to collect accurate, real-time information on both the gas control station's current operations and on emergencies made it necessary to create an automated system for monitoring gas control stations in the REVDAGAZSERVIS gas system.

This system allows gas control stations to send measurements and alarms to distribution centers. The main requirement for the equipment was that it should be highly reliable, which dictated the selection of electronics components from Octagon Systems, including a compact, energy-efficient, PC-compatible Micro PC processor.

The system consists of the operator's station at the gas company's emergency control service, connected via telephone lines to process and event monitors installed at up to 20 control stations.

The monitor uses a 6012 processor (allowing for measurement and control functions on one processor) and a 5524 modem card. The PC-compatible processor, running on DOS, includes an analog-to-digital converter, discrete input/output ports and support for static memory to archive data. The equipment measures incoming and outgoing gas pressure, gas usage and temperature, the temperature in the control station and the pumping potential of gas lines.

The input/output ports relay alerts to indicate high gas levels in the station, high incoming/outgoing gas pressure, dirty filters, safety valve activation and unauthorized access to the station or to the equipment. The equipment also registers emergencies.

The static memory, which holds up to 30 days of data, even in the event of a power outage, records data every five minutes. When the memory is full, operator can choose to stop the recording or to overwrite previously recorded. Data can also be accessed with a portable computer via an RS-232 interface.

The equipment queries all sensors every second, sending an alert in the event of a non-response. Data on emergencies is recorded in a separate archive with the exact time indicated. This archive can record up to 100 such events. Data from both archives can be accessed by the emergency control service.

The operator's PC-compatible control runs the DISPATCHER application, which runs on Windows 3.1.1 and presents sensor data in tables and graphics. The software can prevent repeated emergency signals from being sent, archive data, send out an audible signal in the vent of an emergency, track emergency events and query the control stations automatically or manually. The control station will automatically phone in an alert to the distribution center, which means that the center must have extra phones lines so that the modem will not tie up the line.


A typical gas distribution station where
a control unit is installed.

Example of a process and event monitor with
an open front panel.

By Sergey Zolin, Vitaliy Makhov, Igor Kornienko and Aleskandr Koshta

Sergey Zolin,  Vitaliy Makhov,  Igor Korniyenko,  Aleksandr Koshta