Understanding Heartbeat Message in OCPP 1.6

The heartbeat in OCPP 1.6 (Open Charge Point Protocol) serves as a vital communication signal between the charging station and the central system. It plays a crucial role in reporting the status and connection status of the charging station to the central system. In OCPP 1.6, there are two types of Heartbeat messages: Heartbeat.req and Heartbeat.conf.

The Heartbeat.req message is sent from the Charge Point to the Central System. By default, this request is transmitted every hour, although the Central System has the flexibility to configure a different interval if desired. The purpose of this message is to ensure a continuous and reliable connection between the charging station and the central system.

On the other hand, the Heartbeat.conf message is the response from the Central System to confirm the receipt of the Heartbeat.req request. Additionally, it updates the Heartbeat time of the Charge Point. This confirmation message includes the current time of the Central System, which is provided in the ISO 8601 date and time standard format.

Let’s take a closer look at the JSON format for these Heartbeat messages:

Heartbeat.req:

{
  "chargePointId": "12345"
}

In the Heartbeat.req message, the “chargePointId” field represents the unique identifier of the charger. This identifier helps the central system identify and track the specific charging station.

Heartbeat.conf:

{
  "currentTime": "2023-12-25T08:22:00Z"
}

The Heartbeat.conf message includes the “currentTime” field, which provides the current time of the Central System. This information allows the charging station to synchronize its internal clock and maintain accurate timekeeping.

By exchanging these Heartbeat messages, the charging station and the central system can continuously monitor and verify their connection status. This ensures that any potential disruptions or issues can be promptly detected and addressed.

It’s important to note that the Heartbeat interval can be customized based on specific requirements or network conditions. While the default interval is set to one hour, the Central System can adjust this duration as needed.

Overall, the Heartbeat functionality in OCPP 1.6 plays a crucial role in maintaining a reliable and efficient connection between charging stations and the central system. By periodically exchanging Heartbeat messages, the system can monitor the status of charging stations and promptly respond to any connectivity issues that may arise.