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HMRC internal manual

Oils Technical Manual

Flow Computers: To obtain assurance as to the accuracy of reported volumes

To obtain assurance as to the accuracy of the reported volumes it is necessary toaddress:


The configuration of a flow computer is protected by passwords.

It is reasonable to expect that these passwords are only allocated or accessible toinstrumentation engineers. The configuration of the flow computer can be performed fromthe front panel, through a linked computer system and by using a computer terminal (ascreen and keyboard) connected to the flow computer.

Configuration data

As a minimum a record of all the main system’s configured values should be kept.For certain systems, the configuration data can be archived and restored if required.Incorrect configuration of a replacement system component could have significant revenueeffect.

Alarm handling

Flow computers have the ability to monitor the signals from measurement devices andraise an alarm when the signal is out with a configured range. The configuration of theranges should be commensurate with the metered product and operating conditions.

The action to be taken by the system/operator in response to alarms should be documentedand the actions taken should relate to the significance of the alarm and the frequency ofits occurrence. It can be expected that a log of alarms will be maintained and managementprocedures should be in place to ensure that reasons for unexpected alarms areinvestigated and addressed.