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cFos Power Brain - The Wallbox Controller

The cFos Power Brain is a controller for installation in a wallbox for charging electric cars according to IEC 62196 (type 2). For this purpose, the cFos Power Brain monitors the signals "Charge Pilot" (CP) and "Proximity Pilot" (PP) of the connection cable to the wallbox. A resistor in the cable signals via PP the maximum charge current for which the cable is designed. CP is used to detect the car, monitor ground faults and signal the maximum charge current via PWM

The cFos Power Brain has the following components:

• 230V relay for switching a 3-phase contactor to release the charging current
• optional connection of a DC residual current sensor from Western Automation
• RS 485 interface
• I2C interface for connection of displays and RFID readers
• 2 S0 inputs, potential-free ^(*)
• GPIO Pinheader with numerous analog and digital inputs and outputs
• 230V integrated power supply

^(*) The inputs can be controlled potential-free. Voltage approx. 3.3V to at least 24V. The cFos Power Brain can optionally supply 12V voltage for this.

The heart of the cFos Power Brain is an ESP32 from Espressif Systems. This powerful microcontroller enables the cFos Power Brain to speak the following communication protocols:

• WiFi 802.11 b/g/n, including full TCP/IP stack
• OCPP 1.5 and OCPP 1.6 (SOAP and JSON), both client and backend
• HTTP 1.1
• Modbus TCP and RTU

You can therefore use cFos Power Brain to build a wallbox that speaks OCPP and Modbus at the same time and can also be controlled via an HTTP API. Such wallboxes can then be easily networked via WiFi

The cFos Power Brain can read meters via Modbus, e.g. the ABB B23 112-100 (but also others according to your needs) or up to two S0 meters via the S0 inputs. This allows the wallbox to be equipped with an intermediate meter for billing purposes at a reasonable price and at the same time optionally read other meters from consumers or generators (solar system)

Of course our own EVSE uses the cFos Power Brain.

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