Müller SC28.13 Pro4 1 Channel Astro Time Switch Bluetooth DIN Rail - 16A

The Müller SC28.13 Pro4 is a DIN rail-mounted astro time switch with one 16A switching channel, programmable via Bluetooth from iOS or Android devices. The unit calculates sunrise and sunset times based on geographic location entered during setup, allowing automated switching of outdoor lighting, security lighting and irrigation systems to track seasonal daylight changes without manual reprogramming.

Designed for commercial, industrial and residential electrical distribution boards, the SC28.13 occupies two module widths on standard 35mm DIN rail. The zero-crossing switching technology makes the unit suitable for controlling LED loads up to 600W per channel without flicker or premature lamp failure caused by hard switching at voltage peaks. The LCD display shows current time, programmed events and switch status, with manual override available via the front panel buttons.

The Bluetooth interface removes the need for physical connections during commissioning — programs are built and uploaded via the Müller app, which stores configurations and allows them to be copied across multiple units on larger installations. Daily and weekly schedules can be combined with astro offset programming (e.g. switching 30 minutes after sunset, or 15 minutes before sunrise). A 10-year lithium battery backup retains programs and timekeeping during mains power failures, eliminating the need to reprogram after supply interruptions.

The compact 41mm depth fits typical consumer unit and distribution board enclosures without requiring extended rear space. Screw terminals accept solid or stranded conductors up to 2.5mm², with clearly-marked L, N and switched output positions. The housing is rated for continuous operation at ambient temperatures from -25°C to +55°C, suitable for unheated plant rooms and outdoor enclosures with weatherproof protection.

Product Specification Sheet

Product Manual

How is the astro function programmed?

The Müller app (iOS and Android) connects via Bluetooth and allows you to enter your geographic location. The unit then calculates sunrise and sunset times for that location throughout the year and applies them to your programmed schedule. You can add offsets (e.g. switch on 30 minutes before sunset).

What happens during a power cut?

The 10-year lithium battery backup maintains timekeeping and stored programs during mains failures. When power is restored, the unit resumes the programmed schedule without needing to be reprogrammed or have the time reset.

Can it control LED lighting?

Yes. The zero-crossing switching technology is designed specifically to handle LED loads up to 600W per channel without causing flicker or premature failure. The switch closes at the zero-crossing point of the AC waveform, reducing electrical stress on LED driver circuits.

How many module spaces does it occupy?

The SC28.13 Pro4 occupies two module widths on standard 35mm DIN rail. Check that your distribution board or consumer unit has two adjacent free spaces before ordering.