LED indicators
LED behaviour and diagnostics for firmware v2 hardware variants.
The available LEDs depend on the hardware variant. Firmware v2 uses the status LED for operating state and diagnostics. Separate power and P1 output LEDs, when present, have a fixed hardware function.
P1 Modbus Pro (regular NRGD)
Separate blue mono status LED, green mono power LED on the P1 input and mono P1 output LED
P1 Modbus Pro (ZAP2/NRGDH-based NRGD)
RGB status LED in the P1 input and mono P1 output LED; no separate blue status LED
D1MC
RGB status LED
The old white P1 Modbus adapter uses mono status and power LEDs. It is legacy hardware and is not part of the current hardware comparison.
Power LED
On a regular NRGD, the green LED in the P1 input is on when the adapter has power. During normal operation this LED should stay on continuously. On the ZAP2/NRGDH-based NRGD, an RGB status LED occupies this position instead. If the adapter is off or unstable, check the P1 cable, USB power and smart meter power supply.
P1 output LED
On P1 Modbus Pro, the P1 output LED indicates outgoing P1 data. It blinks when the adapter transmits data on the P1 output. D1MC has no P1 output.
Status LED
On D1MC and the ZAP2/NRGDH-based NRGD, the RGB status LED color indicates the current state. Both implementations use exactly the same RGB colors and indications shown in the table below. On the regular NRGD, the separate blue mono status LED shows the equivalent state without color.
Firmware v1 does not use the RGB status LED behaviour described here. For v1 installations, the status LED is mono.
Startup
Soft white breathing
Soft breathing
The dongle is booting. This normally lasts about 3 seconds.
Ready
Solid blue
On
The dongle is running normally and ready.
Smart meter telegram received
Short green flash
Short blink
A valid smart meter telegram has been received successfully.
Read, parse or Modbus request error
Red pulse
Two short flashes
The dongle detected an error.
RS485 module missing
Three short red flashes, followed by a pause
Three short flashes, followed by a pause
The RS485 module is not detected. Modbus communication is disabled until the module is available again.
Button feedback
When the button is pressed, hardware with an RGB status LED temporarily shows the button action:
Short press
Green while the button is pressed
Reboot the dongle.
Press and hold for more than 5 seconds
Green at first, then red after 5 seconds
Restore factory settings and reboot.
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