Summary #
GHL devices feature a built-in RGB LED behind the GHL logo on the housing cover. It displays the current system status using color and blink codes — providing an at-a-glance overview without opening the software. This article explains the available display modes and the meaning of each color and blink pattern.
Applies to #
- ProfiLux 4 Series (incl. Industrial Line / IL)
- GHL Doser 2 / Maxi / 2.2 Maxi Series (incl. Industrial Line / IL)
- GHL Doser 3 / 3 Maxi Series (incl. Industrial Line / IL)
Display Modes #
Brightness and mode are configured on the General page, in the GHL-logo illumination section. The available modes are listed below; critical states (see Status Codes further down) are always shown regardless of the selected mode.
- Standard: Status notifications are shown blinking. Up to two can be shown simultaneously, alternating between each other.
- Standard without blinking: Status notifications are shown as a steady color instead of blinking. Only the highest-priority active notification is shown at a time. Note that a steady red light in this mode can indicate either an active alarm or a memory defect — open the software to determine the cause.
- Off: The logo LED is disabled. Status notifications are not shown (critical states still override this).
- Constant blue / red / green: The logo is permanently lit in the selected color. Status notifications are not shown (critical states still override this).
Status Codes #
Critical States (always shown, highest priority) #
These states are always displayed regardless of the configured display mode. They take priority over all other notifications and cannot be suppressed.
- Violet blinking: Device is booting.
- Red / Yellow alternating, blinking: Error — problem with the serial number or security key. Contact GHL support.
- Red constant: Error — memory defective. Contact GHL support.
- Yellow constant: Memory has been reset to defaults.
Status Notifications (Standard and Standard without blinking modes) #
The following states are shown in Standard and Standard without blinking modes, in priority order. In Standard mode they blink; in Standard without blinking mode they appear as a steady color. Up to two states can be active simultaneously in Standard mode — they alternate. In Standard without blinking mode, only the highest-priority active state is shown.
- Red: Alarm active.
- Yellow: Warning active. Only shown if no alarm is present.
- Green: Activity in progress, e.g. dosing or water change.
- White: Connecting to myGHL.
- Blue blinking / Blue constant: myGHL connected (blinking in Standard mode). If no other state is active and myGHL is not in use, the logo shows a steady blue as an idle indicator.