[Technology] What is OCPP protocol? | by youssef belmkaddem | Medium

OCPP stands for Open Charge Point Protocol. It’s a set of rules and standards that govern the communication between the Electric Vehicle Charging Stations of different vendors with different Charging Station Management Systems (CSMS).

In my previous article, What is IoT? I explained how a machine communicates with another machine by using the 4 layers of the TCP/IP model. OCPP is just the language of the EV charger and works at the application layer. Electric Vehicle Charging

More information about the TCP/IP model can be found in my article here.

You may be asking why we should have a communicating EV charger. The answer is simple. When the EV charger exchanges data with the Charging Station Management System (CSMS) it is constantly telling you about its state of health. Believe me, a lot of “health” problems can be solved remotely, and if not, this communication will let you know exactly what component should be replaced. Besides this, connectivity for EV chargers will be a must when having a smart grid. We should have control over the Production/Consumption of electricity in order to avoid blackouts.

OCPP was established in 2009 by the Open Charge alliance. The aim was to create an open communication standard that would allow the Dutch Charging Stations (CS) and Charging Station Management Systems (CSMS) from different vendors to easily communicate with each other. The OCPP protocol is now spreading over the world. So let’s dig a bit more into this unique language.

There are two different flavors of OCPP. OCPP JSON (OCPP-J) over WebSocket and OCPP SOAP (OCPP-S). For those unfamiliar with protocol communication, the main purpose of SOAP Simple Object Access Protocol and JSON JavaScript Object Notation is to convert the data in an easy format in order to be transported. The JSON uses the WebSocket as a transporter and SOAP uses in most cases HTTP. The performance of the WebSocket is much higher. Thus the OCPP-J is the most commonly used language between the Charging Station and the Charging Station Management Systems.

Let’s have a look at how this language is written. Below I will only focus on the OCPP-1.6J.

This version of the OCPP has 6 profiles, and each profile has several messages.

Now, let’s dive into each of these profiles!

This profile includes all the messages required to make use of the basic functionality of the OCPP.

This profile is about updating the firmware of the Charging station and getting diagnostics logs when required. For those who don’t know what logs mean, it is simply important information gathered by the machine during its lifecycle. And for those who don’t know what firmware is, please check my previous article: What is a firmware?

Let us now move forward. The Firmware management profile includes 4 messages:

3. Local Auth List Management Profile

Sometimes having connectivity can be difficult. This profile is intended for the station to work in an offline mode. In order to identify, the station will use local authorization. Authorization Cache and/or a Local Authorization List are used for this purpose.

This profile got two messages:

TriggerMessage — this is the only message on this profile. It is used to trigger those messages:

(BootNotification, DiagnosticsStatusNotification, FirmwareStatusNotification, Heartbeat, MeterValues, StatusNotification)

OCPP 1.6 does not support scheduling a reservation for a future date, it can only reserve at the exact time of reservation. This profile contains the following messages:

This profile is the only added feature of the OCPP 1.6 compared to its predecessor the OCPP 1.5. It is all about controlling power consumption by limiting charging parameters. We can find 3 different messages:

Here is an example of creating a charging Profile:

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