Photoperiod, holds and catch-up

The hub's lights clock, auto photoperiod, sunrise/sunset ramps, the dark-period guard, manual light hold, catch-up and its surprises, the 4×8 open loop and lamp plugs, and how schedule shifts are confirmed.

Each tent's lights-on time and hours are hub numbers. The hub keeps time by SNTP when it has internet, otherwise from the time you set at fleet setup. Settings › System › Time shows the hub clock and drift; CLOCK INVALID means the photoperiod cannot be trusted until it syncs.

With Automatic photoperiod on, the hub ramps the SF1000 up over the sunrise minutes at lights-on, holds the target brightness, ramps down over sunset, and keeps the lamp off for at least minimum dark hours. A lamp on during the protected dark period is a critical dark period violation, and the violation stays visible even if the reading later goes stale.

A hold freezes the lamp at its current on/off and brightness and stops the schedule, and any active catch-up, from moving it. It is meant for a few minutes of work under the lamp. The dashboard shows the roll-on a toggle will cause before you confirm, and journals it.

After an outage or a hold, the hub may run catch-up to make up missed lit hours inside the day. Releasing a hold while catch-up is active turns the lamp ON immediately. Cancel catch-up on the Light desk writes off the hours still owed for this cycle only: the lamp returns to the normal window and tomorrow's schedule is unchanged. It does not turn the lamp off by itself while the normal window is open. A hub whose firmware lacks the control shows a note instead of the button; there, keep the hold on until the window ends. Full Auto and the mister have the same release pattern.

The 4×8 has no hub lamp output and no lamp sensor. Its photoperiod is a clock only; the desk shows the schedule, not a lamp. Two ways to close the loop:

• Bind a smart plug as Lamp plug · 4×8. The brain then switches it with the hub's window. On/off only, and leave an off-only schedule on the plug so a brain outage cannot strand the lamp on. While a Safety cut-off is active the plug is held off, whatever the window says.
• Bind a lux sensor to the tent to at least confirm lit state. The 4×8 Got hours count the lamp plug's reported on-time when the plug has reported since midnight (power at the socket, not a light reading), else the twin-lamp history when a lamp output exists, else the schedule window.

Moving a lights-on time, shifting a window or flipping to 12/12 is an explicit action: the brain shows the plan and requires confirm; a shift without confirm is refused. Learning surfaces a suggestion when energy or timing outliers become the norm; it never acts on one growth-priority day.

The SF1000's hardware dimming knob overrides the hub's brightness. The light control path row on the Light desk says what DSC drives and what overrides it.

Guide contents  ·  How it works  ·  Troubleshooting  ·  Digital Stealth Care

DSC-Brain user guide · Photoperiod, holds and catch-up · this page is edited on the site; the Notion original was retired after the mirror