Nextion
Controller provide Nextion API that is universal (not strictly define pages or components placement on pages).
Nextion API can be set in serial settings, any serial interface can be operating in Nextion API mode. Only one interface can work in Nextion API mode!
Commands can be send from Nextion Display to controller, must be terminated with 0xFF 0xFF 0xFF. In Nextion editor set encoding to UTF-8.
Before connecting Nextion display to controller check display datasheet for Output High Voltage. Intelligent series has 5V TX, but ESP32 is only 3V3 tolerant! If board design not contains logic level converter, use external voltatage divider.
| Command | Description |
|---|---|
| sub <variable> | Subscribe to variable |
| unsub | Unsubscribe to all variables |
| en <value> | Set charging enabled value must be 0 or 1 |
| chCur <value> | Set charging current in A*10 |
| consumLim <value> | Set consumption limit in Wh |
| chTimeLim <value> | Set charging time limit in s |
| uPowerLim <value> | Set under power limit in W |
| auth | Authorize to start charging when is pending |
To access variable in Nextion display, must be defined component with objname (variable, text, number, dual-state button, slider, etc.) from following table. To receive variable value from controller, subscribe to variable with sub command.
| Variable | Description | Type |
|---|---|---|
| state | EVSE state (A, B0, B1, C0, C1, D0, D1, E, F) | string |
| en | Charging enabled (enabled=1, disabled=0) | number |
| err | Error bits | number |
| pendAuth | Pending authorization before start charging, when authorization is required (1 when pending otherwise 0) | number |
| limReach | Charging limit reached (1 when any charging limit reached otherwise 0) | number |
| maxChCur | Maximum charging current in A | number |
| chCur | Charging current in A*10 | number |
| sesTime | Session time in s | number |
| power | Charging power in W | number |
| consum | Consumption in Wh | number |
| vltL1 | L1 voltage in V*100 | number |
| vltL2 | L2 voltage in V*100 | number |
| vltL3 | L3 voltage in V*100 | number |
| curL1 | L1 current in V*100 | number |
| curL2 | L2 current in V*100 | number |
| curL3 | L3 current in V*100 | number |
| consumLim | Consumption limit in Wh | number |
| chTimeLim | Charging time limit in s | number |
| uPowerLim | Under power limit in W | number |
| devName | Device name | string |
| uptime | Uptime in s | number |
| temp | Temperature (highest) in dg.C*100 | number |
| ip | WiFi station IP address | string |
| appVer | App version | string |
| heap | Used heap size | number |
| maxHeap | Max heap size | number |
Controlling charging current and charging enabled
Define dual-state button with objname en, slider with objname chCur and string variable with objname str.
Set page preinitialize event:
Set slider touch release event:
Set dual-state button touch press event:
For advanced Nextion HMI visit https://github.com/dzurikmiroslav/esp32-evse-nextion