What is OCPP?
Open Charge Point Protocol
OCPP is the open protocol that EV chargers use to talk to a CMS (CPMS). It covers starting and stopping sessions, authorising drivers, reporting meter values and faults, remote commands and firmware updates. OCPP 1.6J (JSON over WebSocket) is the most widely deployed version; OCPP 2.0.1 adds device management, better security and smart charging features. It is maintained by the Open Charge Alliance (OCA).
Under OCPP, the charger opens a connection to the management system (the CSMS) and the two exchange messages such as BootNotification when a charger starts, Authorize and StartTransaction (in 2.0.1, TransactionEvent) for sessions, MeterValues for energy readings and StatusNotification for availability and faults.
OCPP 2.0.1 is not backwards compatible with 1.6J, so a management system that supports both lets an operator run older and newer chargers side by side. OCPP also carries smart charging limits from the management system to each charger.
Iris supports OCPP 1.6J and 2.0.1 and is integrated with chargers from 35+ manufacturers.