FC Flow Computer
5
Step3:ComputetheVolumetricFlow-
Volumetricowisthetermgiventotheowinvolumeunits.
The value is computed based on the owmeter input type
selected and augmented by any performance enhancing
linearizationthathasbeenspeciedbytheuser.
Step4:ComputetheCorrectedVolumeFlowatReference
Conditions-
Inthecaseofacorrectedliquidorgasvolumeowcalculation,
the corrected volume ow is computed as required by the
selectedcompensationequation.
Step5:ComputetheMassFlow-
Allrequiredinformationisnowavailabletocomputethemass
owrateasvolumeowtimesdensity.Aheatowcomputation
isalsomadeifrequired.
Step6:CheckFlowAlarms-
The ow alarm functions have been assigned to one of
the above ow rates during the setup of the instrument.A
comparisonisnowmadebycomparingthecurrentowrates
againstthespeciedhiandlowlimits.
Step7:ComputetheAnalogOutput-
Thisdesignatedowratevalueisnowusedtocomputethe
analogoutput.
Step8:ComputetheFlowTotalsbySummation-
A ow total increment is computed for each ow rate. This
incrementiscomputedbymultiplyingtherespectiveowrate
byatimebasescalerandthensumming.Thetotalizerformat
alsoincludesprovisionsfortotalrollover.
Step9:PulseOutputService-
Thepulseoutputisnextupdatedbyscalingthetotalincrement
whichhasjustbeendeterminedbythepulseoutputscalerand
summingittoanyresidualpulseoutputamount.
Step10:UpdateDisplayandPrinterOutput-
Theinstrumentnallyrunsatasktoupdatethevarioustable
entries associated with the front panel display and serial
outputs.
Instrument Setup
Thesetupispasswordprotectedbymeansofanumericlock
outcodeestablishedbytheuser.Thehelplineandunitsof
measurepromptsassureeasyentryofparameters.
An EZ Setup function is supported to rapidly congure the
instrument for rst time use. A software program is also
available which runs on a PC using a RS-232 Serial for
connectiontotheFlowComputer.Illustrativeexamplesmay
bedownloadedinthismanner.
The standard setup menu has numerous subgrouping of
parameters needed for ow calculations. There is a well
conceived hierarchy to the setup parameter list. Selections
made at the beginning of the setup automatically affect
offeringsfurtherdowninthelists,minimizingthenumberof
questionsaskedoftheuser.
In the setup menu, the ow computer activates the correct
setup variables based on the instrument conguration, the
ow equation, and the hardware selections made for the
compensation transmitter type, the ow transmitter type,
andmeterenhancements(linearization)optionsselected.All
requiredsetupparametersareenabled.Allsetupparameters
notrequiredaresuppressed.
Alsonotethatinthemenuareparameterselectionswhichhave
preassignedindustrystandardvalues.Theunitwillassume
thesevaluesunlesstheyaremodiedbytheuser.
Mostoftheprocessinputvariableshaveavailablea“default”
oremergency valuewhich mustbe entered.Theseare the
valuesthattheunitassumeswhenamalfunctionisdetermined
tohaveoccurredonthecorrespondinginput.
It is possible to enter in a nominal constant value for
temperature or density, or pressure inputs by placing the
desirednominal value intothe default valuesand selecting
"manual".Thisisalsoaconveniencewhenperformingbench
toptestswithoutsimulators.
Thesystemalsoprovidesaminimumimplementationofan
“audittrail”whichtrackssignicantsetupchangestotheunit.
This feature is increasingly being found of benet to users
or simply required by Weights and Measurement Ofcials
in systems used in commerce, trade, or “custody transfer”
applications.
Simulation and Self Checking:
Thismodeprovidesanumberofspecializedutilitiesrequired
forfactory calibration,instrumentcheckoutonstart-up, and
periodiccalibrationdocumentation.
A service password is required to gain access to this
specializedmodeof operation.Normallyquality, calibration,
andmaintenancepersonnelwillndthismodeofoperation
veryuseful.
Manyofthese tests maybe used duringstart-upof a new
system.Outputsignalsmaybeexercisedtoverifytheelectrical
interconnectsbeforetheentiresystemisputonline.
ThefollowingactionitemsmaybeperformedintheDiagnostic
Mode:
PrintCalibration/MaintenanceReport
ViewSignalInput(Voltage,Current,Resistance,Frequency)
ExamineAuditTrail
PerformaSelfTest
PerformaServiceTest
ViewErrorHistory
PerformPulseOutputCheckout/Simulation
PerformRelayOutputCheckout/Simulation
PerformAnalogOutputCheckout/Simulation
CalibrateAnalogInputsusingtheLearnFeature
CalibrateAnalogOutputusingtheLearnFeature
ScheduleNextMaintenanceDate
Notethatacalibrationoftheanaloginput/outputwilladvance
the audit trail counters since it effects the accuracy of the
system.
