This working group focusses on the communication between the charging station (EVerest) and the management system(s) (CPMS)
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Meeting Notes:
9 October 2024 (OCPP 2.1 Architecture brainstorm)
1.1 Message Handling
* Question: Can we just use the OCPP2.1 message types in message handlers?
1.2 Schemas
* Contain some change in lengths of properties (e.g. exiResponse)
* Remarks to the draft can be added to public Excel sheet from the OCA
1.3 Other topics to discuss:
* Storage abstraction (Device Model + Internal Database)
* Switching between protocol versions at runtime
* Connectivity Management
* Simplifying the charge point interface to simplify adding more functional blocks
2.1 RPC Framework extensions
* SEND: unidirectional, no ack, outside of synchronous behavior of rpc framework
* CALLRESULTERROR: Only allowed in 2.1 not 2.0.1
2.2 Websocket Subprotocol
* WS handshake specifices the OCPP version to use, not the device model settings
3 Things to investigate
* How to deal with message fields that are longer in 2.1 than in 2.0.1. We can receive the longer messages but should we limit when sending and if so, how?
4 Preliminary design decisions
* Use OCPP2.1 message types in the implementation for both 2.0.1 and 2.1
* OCPPChargingStation base class required to do initial websocket handshake and select protocol version based on that
5 Migrating to another CSMS
* All transaction should have finished, then Reset
* If switching between protocol versions we might have issues with messages from another protocol version in the message queue: Empty message queue when switiching protocol versions?
* Document how a proper transition could look like (wipe data if required, stop running transactions, etc.)
6 Date for F2F
Focus on October 22nd and have 23rd spare
2 October 2024
Feature Freeze:
- Some issues found during testing.
- Second release candidate 2024.9.0-rc2 coming soon
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