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High level tank alarm monitoring for fuel sites

Edited by the Processingtalk editorial team Mar 24, 2008

Following the publication of the 'Buncefield' Incident report relating to fuel and oil storage sites, Omniflex have produced a remote high level tank alarm monitoring system for these applications

The system consists of Maxiflex remote terminal units (RTU) which are located around the facility, each capable of receiving analogue and digital alarm inputs then multiplexing this data over any network type (even two cores of an existing cable could be used to save on network cabling) to a control room for alarm logging and displaying on alarm annunciator displays.

A further Maxiflex RTU which accepts digital inputs for local alarms is based in the central control room.

This RTU has a relay output module fitted which provides outputs to drive a horn and beacon and at the same time provides the means by which the integrity of the communications link, between the tank farm Maxiflex RTUs and the control room, is monitored.

The relay output module also provides an Alarm 'watchdog' output into a hard-wired IEC61508 SIL1 assessed Omni 16C alarm annunciator.

The control room Maxiflex RTU also provides a Modbus link into a SCADA / DCS system for further logging and display and to Omni-X LED Annunciator display panels via Omni16c Remote Alarm Logic units.

The ultimate test of any industrial product is in service, and the Maxiflex and IEC61508 SIL1 Omni 16C alarm annunciator system is relied upon by many major industries 24 hours a day, seven days a week.

These provide a very large installed base all over the world, and have proved over the years to be extremely reliable.

Some major benefits of using the Maxiflex RTU over other PLCs are:.

* Totally modular design.

* Single Channel architecture design.

* Very easy expansion.

* Totally open system architecture allowing other 3rd party systems to interface if required in the future.

* Total flexibility with communications from any type of network whether it is existing 2 cores of a copper cable (CONET up to 10kms without repeaters), fibre including the blown fibre networks, radio, PSTN, GSM, GPRS, Modbus, Ethernet etc.

* It can perform all Alarm Annunciator functionality.

* Totally distributed in design, enabling the Maxiflex units to be located anywhere on site and be inter-connected via any network back to SCADA / DCS systems.

The Maxiflex I/O system is extremely diverse in its use and is already being used for Data Acquisition, Control IEC61131-3, Alarm/Event monitoring, Alarm Annunciation, Sequence of event monitoring to 1milli-second resolution on digital inputs.

The system totally restores in the event of a power failure, the I/O can be unplugged and replaced without the need to remove the power from the node "Hot swap" is a standard feature.

* Any Maxiflex I/O node can be removed from the network without the loss of communication to other Maxiflex I/O nodes.

* All Analogue inputs are fully inter-channel isolated to 500vac rms and have input to logic isolation of 1500vac rms.

* The Maxiflex system is proven in use and has a 97 year MTBF based on figures of modules returned to factory.

* All equipment meets the EMC codes and practices .

* Complete diagnostics down to the I/O module level with complete self-testing.

For more information please contact Omniflex UK.