How can I adjust the Heartbeat interval on zappi?

Introduction 

Heartbeats are used within OCPP to allow the charge point and the central system to ensure the charger still has an active connection. Your OCPP service provider may have a preferred interval at which such messages should be sent. 

You can adjust the heartbeat interval by changing the HeartbeatInterval parameter in the OCPP configuration. This is defined in seconds. 

Note: If the central system responds with a heartbeat interval within the bootNotification, zappi will automatically adhere to this interval. If no such interval is set, zappi will default to 60 seconds.