Powermeter OCMF Handling

This document explains how EVerest modules implementing the powermeter interface shall handle OCMF report generation and transmission when used in conjunction with the EvseManager module.

The following sequence diagrams illustrate the interactions between the involved modules during the start and stop of a transaction, including error handling scenarios:

• Start of a transaction

• Stopping transaction in error

• Start of Powermeter or recovery after communication loss

Start of a transaction

        sequenceDiagram
   autonumber
   participant Powermeter
   participant EvseManager
   participant OCPP
   participant CSMS

   title Start of a Transaction

   Note over EvseManager: User plugs in EV and authorizes

   EvseManager->>OCPP: Event(SessionStarted)

   OCPP->>CSMS: StatusNotification.req(Preparing)
   CSMS-->>OCPP: StatusNotification.conf

   alt successful case
       EvseManager->>Powermeter: startTransaction
       Powermeter-->>EvseManager: startTransaction Response (OK/ID)

       EvseManager->>OCPP: Event(TransactionStarted)
       OCPP->>CSMS: StartTransaction.req
       CSMS-->>OCPP: StartTransaction.conf

       Note over EvseManager: Transaction started successfully

   else startTransaction failing due to power loss
       EvseManager->>Powermeter: startTransaction
       Powermeter-->>EvseManager: startTransaction Response (FAIL)

       EvseManager->>OCPP: Event(Deauthorized)

       OCPP->>CSMS: StatusNotification.req(Finishing)
       CSMS-->>OCPP: StatusNotification.conf

       EvseManager->>OCPP: raiseError (PowermeterTransactionStartFailed)
       OCPP->>CSMS: StatusNotification.req(Finishing, PowermeterTransactionStartFailed)
       CSMS-->>OCPP: StatusNotification.conf

       Note over EvseManager: Transaction did not start
   end

   alt EvseManager configured to become inoperative in case of Powermeter CommunicationError
       Powermeter->>EvseManager: raise_error(CommunicationError)
       Note over Powermeter,EvseManager: Powermeter raises a CommunicationError <br/>and EvseManager is registered for notification
       EvseManager->>OCPP: raise_error (Inoperative)
       OCPP->>CSMS: StatusNotification.req(Faulted)
       CSMS-->>OCPP: StatusNotification.conf
   end


    

Stopping Transaction in Error

        sequenceDiagram
   autonumber
   participant Powermeter
   participant EvseManager
   participant OCPP
   participant CSMS

   title Stopping Transaction in Error

   Note over Powermeter, CSMS: Transaction is running

   Powermeter->>Powermeter: detects a <br/> CommunicationError
   Note over Powermeter,EvseManager: Powermeter raises a CommunicationError <br/>and EvseManager is registered for notification
   Powermeter->>EvseManager: raise_error (CommunicationFault)
   Powermeter->>OCPP: raise_error (CommunicationFault)

   OCPP->>CSMS: StatusNotification.req(Charging, CommunicationFault)
   CSMS-->>OCPP: StatusNotification.conf

   alt EvseManager configured to become inoperative in case of PowermeterCommError
       EvseManager->>EvseManager: Pause charging
       EvseManager->>OCPP: raiseError (Inoperative)
       OCPP->>CSMS: StatusNotification.req(Faulted)
       Note over EvseManager: Note that we would just continue charging otherwise
   end

   Note over Powermeter, CSMS: User stops the transaction

   alt successful case (Powermeter has no CommunicationError)
       EvseManager->>Powermeter: stopTransaction (ID)
       Powermeter-->>EvseManager: stopTransaction Response (OK/OCMF)
       EvseManager->>OCPP: Event(TransactionFinished(OCMF))

       OCPP->>CSMS: StopTransaction.req(OCMF)
       CSMS-->>OCPP: StopTransaction.conf
   else stopTransaction failing due to subsequent power loss (this applies as well when Powermeter still in CommunicationError)
       EvseManager->>Powermeter: stopTransaction (ID)
       Powermeter->>EvseManager: stopTransaction Response (FAIL)
       EvseManager->>OCPP: Event(TransactionFinished)

       Note right of OCPP: In this case we can't stop the transaction including the OCMF
       OCPP->>CSMS: StopTransaction.req()
       CSMS-->>OCPP: StopTransaction.conf
   end


    

Start of Powermeter or recovery after communication loss

        sequenceDiagram
  autonumber
  participant Powermeter
  participant EvseManager

  title Start of Powermeter or recovery after communication loss

  Note over Powermeter: Device communication (re)established

  Powermeter->>Powermeter: Request status from device
  Powermeter->>Powermeter: Detects a running transaction
  Powermeter->>Powermeter: Mark need_to_stop_transaction to true

  alt Next command is startTransaction
      EvseManager->>Powermeter: startTransaction
      Powermeter-->>Powermeter: stopTransaction
      Note over Powermeter: internal triggered stopTransaction will not send <br>a response to EvseManager since no stopTransaction was issued
      Powermeter->>Powermeter: Mark need_to_stop_transaction to false
      Powermeter-->>EvseManager: startTransaction Response (OK/ID)
      Powermeter->>Powermeter: Mark need_to_stop_transaction to true

      Note over EvseManager: Transaction started successfully

  else Next command is stopTransaction
      EvseManager->>Powermeter: stopTransaction
      Powermeter-->>EvseManager: stopTransaction Response (OK/OCMF)
      Powermeter->>Powermeter: Mark need_to_stop_transaction to false
  end

  Note over Powermeter: In case of CommunicationError during start/stop<br> transaction please check the start/stop transaction diagrams


    

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Authors: Florin Mihut, Piet Gömpel