C-Bus schedules, timers and the Enable application

One of the questions we field most often once a C-Bus system is up and running is some version of: “Can the lights just do their own thing?” Turn the garden lights on at dusk, drop the heating back at midnight, switch the pool pump for three hours and then stop — without anyone touching a switch. The good news is yes, absolutely. The slightly less obvious part is that C-Bus has a few different ways of handling time-based control, and which one you’ve got depends on how your system was built and what hardware lives in your switchboard.

In this article we’ll walk through where time control actually comes from in a C-Bus network, how a humble switch can act as a timer, and the often-overlooked Enable application that lets you switch whole chunks of automation on and off — the closest thing C-Bus has to a “we’re on holidays” button.

Where time-based control comes from

C-Bus itself is just a network of units talking on the pink cable. The cable doesn’t know what time it is. To run anything to a clock, you need a device on the network that does keep time and can issue commands on schedule. In practice that’s one of two things:

• A controller with a clock and a schedule engine. This is a Programmable Automation Controller (the C-Bus PAC), a Wiser Home Controller, or one of the older C-Touch / colour touchscreen units. These hold the date and time, run sunrise/sunset calculations for your location, and fire off scheduled events.
• A Key Input Unit programmed as a timer. Switches like the Saturn, Saturn Zen, Neo and the DLT/eDLT range can be configured so that a button doesn’t just toggle a light — it kicks off a timed sequence that switches something on and then turns it back off after a set period.

The distinction matters because it tells you who you’ll need to involve when you want to change a time. A controller schedule is one thing; a timer baked into a switch is another, and we’ll cover both.

Switches that double as timers

The simplest form of time control needs no controller at all. Key Input Units can be set to a timer function in C-Bus Toolkit using Learn Mode. The classic example we set up for customers is the bathroom heat lamp or exhaust fan: press the button, the fan runs for, say, fifteen minutes, then switches itself off so it’s not droning away all afternoon.

Under the hood, the key is programmed to set a Lighting group (application 56) to a level, hold it for a defined time, then ramp it back to off. You can also do “on for a period then back to the previous state,” which is handy for path lighting and outdoor areas.

These unit-level timers are configured directly on the input unit via Toolkit — there’s no logic engine involved, which makes them reliable and self-contained. The trade-off is that they’re fixed: the duration is set in the unit’s programming. Changing fifteen minutes to thirty is a Toolkit edit, not something you’d do from a phone.

Setting a simple timer (the short version)

1. Connect to the network with a PCI, CNI or 5500PCU and open C-Bus Toolkit.
2. Scan the network and locate the Key Input Unit you want to use.
3. Put the unit into Learn Mode and select the relevant channel/button.
4. Change its action from a standard toggle to a timer function, then set the on-level, ramp rate and the duration before it switches off.
5. Save the changes back to the unit and test the button on site.

Schedules on a controller, and why PICED matters

For anything genuinely scheduled — astronomical (sunset/sunrise) events, day-of-week routines, multi-step sequences, “if it’s a weekday and after 6pm” logic — you need a controller, and that controller is programmed in PICED. PICED is the design software for the PAC, Wiser and C-Touch family, and it contains the Logic Engine where schedules and timer logic are built.

The Logic Engine is where the real intelligence lives. We use it to write rules like “at sunset, ramp the facade lights to 80% over thirty seconds,” or “every weeknight at 11pm, set the whole house to a low Night scene unless someone is still up.” Sunrise and sunset are calculated from your latitude and longitude, so they track through the seasons automatically — no quarterly tinkering with clock times. Once written, the logic is downloaded to the controller, which then runs independently of any computer.

This is also why a request to “just move the garden lights to come on half an hour later” sometimes means a visit. If the schedule is hard-coded in the Logic Engine and not exposed as an adjustable setting, changing it is an integrator edit in PICED. Where we know a customer will want to tweak times, we deliberately expose them — as a schedule you can edit in the Wiser app or as a slider on a touchscreen page — so you’re not ringing us for every daylight-saving changeover. It’s worth raising this with us up front; we’d much rather build it adjustable from day one. There’s more on this in our C-Bus programming articles.

The Enable application — your holiday switch

Here’s the feature most people don’t know they have. The Enable Control application (application 203) exists specifically to turn whole functions or blocks of logic on and off. Think of it as a master gate in front of your automation.

A controller’s Logic Engine can be set to only run a piece of logic when a particular Enable group is “on.” So you might group all of your automatic routines — schedules, motion-triggered lighting, the irrigation timer — behind a single Enable group called something like “Auto Enabled.” Switch that Enable off and the house stops automating. Switch it back on and everything resumes exactly as programmed.

The obvious use is going away. When you head off for a fortnight you might want a holiday presence routine to run, but you definitely don’t want the morning “open the blinds and warm the bathroom” sequence firing for an empty house. A well-built system lets you flip a single Enable to swap modes. We also use Enable groups to suspend motion-activated lighting during a party, or to lock out automation in a media room while a film’s on.

Enable groups can be driven from a button, a touchscreen, the Wiser app, or by other logic. It’s one of the cleaner ways to give you real control without us having to re-edit schedules every time your routine changes. If you’d like a holiday or away mode added, that’s a quick win — see our C-Bus automation guides or get in touch.

Letting sensors drive the schedule

Time isn’t the only thing automation can respond to. The Measurement application (application 228) lets sensors report live values onto the network — temperature, light level, humidity and the like — which the Logic Engine can then read and act on.

This is where things get genuinely smart. Instead of “turn the lights on at 5:30pm,” you can write “turn the lights on when the measured outdoor light level drops below a threshold,” so a gloomy overcast afternoon is handled properly and a bright summer evening isn’t lit unnecessarily. Combine the two — “if it’s after 4pm and light level is low” — and you get behaviour that feels intuitive rather than rigidly clock-driven. Temperature measurements can nudge heating or trigger a fan, and the values can be displayed on your touchscreen or app too.

Measurement-based automation does need compatible sensors and a controller to interpret the data, so it’s something we’d scope as part of the design rather than retrofit casually. If you’re curious whether your existing kit can report these values, the project file will tell us straight away.

So which one have you got?

To pull it together:

• Simple on-for-a-while timers live in the Key Input Units, set in Toolkit. Self-contained, reliable, fixed duration.
• Real schedules (sunset events, weekday routines, sequences) live in a controller’s Logic Engine, built in PICED.
• Enable (203) switches whole functions or schedules on and off — perfect for away and holiday modes.
• Measurement (228) brings sensor values into the mix so automation can respond to conditions, not just the clock.

If your schedules aren’t doing what you expect, or events seem to fire at the wrong time, the culprit is often the controller’s clock or network time — our troubleshooting guides cover that. For the official application overview, Clipsal’s documentation at clipsal.com is the authoritative reference.

That’s the lay of the land on time and conditional control in C-Bus. Nine times out of ten when a customer rings us wanting their lights or heating to “just know what to do,” the answer is a tidy bit of Logic Engine work plus a sensible Enable group so they stay in charge. If you’re in Melbourne and want schedules built, holiday modes added, or simply want to be able to change your own times from the app, drop us a line via our contact page — happy to help.

— Adam and the DUKE team