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  <xs:element id="omcl_ScheduleOfCapitalizedComputerSoftwareNetTableTextBlock" abstract="false" name="ScheduleOfCapitalizedComputerSoftwareNetTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:textBlockItemType"/>
  <xs:element id="omcl_OneMonthSecuredOvernightFinancingRateSOFRApplicableMarginMember" abstract="true" name="OneMonthSecuredOvernightFinancingRateSOFRApplicableMarginMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="omcl_ScheduleOfShareBasedCompensationFutureIssuanceOfSharesTableTextBlock" abstract="false" name="ScheduleOfShareBasedCompensationFutureIssuanceOfSharesTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:textBlockItemType"/>
  <xs:element id="omcl_ContractWithCustomerLiabilityCustomerAdvancesAndDepositsCurrent" abstract="false" name="ContractWithCustomerLiabilityCustomerAdvancesAndDepositsCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="omcl_ScheduleOfFutureAmortizationExpensesForCapitalizedSoftwareDevelopmentCostsTableTextBlock" abstract="false" name="ScheduleOfFutureAmortizationExpensesForCapitalizedSoftwareDevelopmentCostsTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:textBlockItemType"/>
  <xs:element id="omcl_DebtInstrumentCovenantMaximumSecuredNetLeverageRatio" abstract="false" name="DebtInstrumentCovenantMaximumSecuredNetLeverageRatio" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="omcl_DebtInstrumentConvertibleMaximumCash" abstract="false" name="DebtInstrumentConvertibleMaximumCash" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="omcl_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsPurchasedInPeriodWeightedAveragePrice" abstract="false" name="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsPurchasedInPeriodWeightedAveragePrice" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:perShareItemType"/>
  <xs:element id="omcl_CapitalizedComputerSoftwareAmortizationYearThree" abstract="false" name="CapitalizedComputerSoftwareAmortizationYearThree" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="omcl_ContractWithCustomerLiabilityCurrentGross" abstract="false" name="ContractWithCustomerLiabilityCurrentGross" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="omcl_DebtInstrumentConvertibleConsiderationInExcessAmount" abstract="false" name="DebtInstrumentConvertibleConsiderationInExcessAmount" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="omcl_DebtInstrumentCovenantMinimumInterestCoverageRatio" abstract="false" name="DebtInstrumentCovenantMinimumInterestCoverageRatio" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="omcl_CustomerFundLiabilityCurrent" abstract="false" name="CustomerFundLiabilityCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="omcl_CapitalizedComputerSoftwareAmortizationYearTwo" abstract="false" name="CapitalizedComputerSoftwareAmortizationYearTwo" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="omcl_PaymentsForSoftwareForExternalUse" abstract="false" name="PaymentsForSoftwareForExternalUse" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="omcl_A2009PlanMember" abstract="true" name="A2009PlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="omcl_AccruedGroupPurchasingOrganizationFees" abstract="false" name="AccruedGroupPurchasingOrganizationFees" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="omcl_LesseeOperatingLeaseLiabilityToBePaidAfterYearFour" abstract="false" name="LesseeOperatingLeaseLiabilityToBePaidAfterYearFour" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="omcl_CapitalizedComputerSoftwareAmortizationYearOne" abstract="false" name="CapitalizedComputerSoftwareAmortizationYearOne" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="omcl_DeferredTaxAssetConvertibleDebtHedge" abstract="false" name="DeferredTaxAssetConvertibleDebtHedge" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="omcl_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageRemainingTermAbstract" abstract="true" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageRemainingTermAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="omcl_DebtInstrumentRedemptionFaceAmountOfNotesThatMustBeOutstanding" abstract="false" name="DebtInstrumentRedemptionFaceAmountOfNotesThatMustBeOutstanding" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="omcl_ProceedsFromPaymentsForCustomerFundsNet" abstract="false" name="ProceedsFromPaymentsForCustomerFundsNet" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="omcl_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageRemainingTermAbstract" abstract="true" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageRemainingTermAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="omcl_DebtInstrumentAccordionFeatureIncreaseLimit" abstract="false" name="DebtInstrumentAccordionFeatureIncreaseLimit" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="omcl_ScheduleOfInterestExpenseDebtTableTextBlock" abstract="false" name="ScheduleOfInterestExpenseDebtTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:textBlockItemType"/>
  <xs:element id="omcl_RevenueFromContractWithCustomerMaximumContractTerm" abstract="false" name="RevenueFromContractWithCustomerMaximumContractTerm" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="omcl_AdjustmentsToAdditionalPaidInCapitalConvertibleNoteHedge" abstract="false" name="AdjustmentsToAdditionalPaidInCapitalConvertibleNoteHedge" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="omcl_RestrictedStockRSAsRestrictedStockUnitsRSUsAndPreformanceSharesPSUsMember" abstract="true" name="RestrictedStockRSAsRestrictedStockUnitsRSUsAndPreformanceSharesPSUsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="omcl_IncreaseDecreaseInPrepaidCommissions" abstract="false" name="IncreaseDecreaseInPrepaidCommissions" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
</xs:schema>
