Fan Control (again) using either 3 relays or a sweep fan relay ?

Hello all,
I've read a bunch of forum articles about using the sweep fan relay where they either use 1 button (toggle between speeds) or 4 (1 button per speed).

I've got a number of rooms with 6 button Saturn switches which I've allocated 3 buttons (one column) for lights and 3 for fan speed. The intention of having 3 buttons for the fan was as follows:

• Press button #1 for full speed
• Press button #2 for medium speed
• Press button #3 for slow speed
• If the fan is running (at any speed), then pressing the corresponding button will turn the fan off.

At the moment, I've only configured one switch to turn the fan on/off via a single relay (which bypasses the capacitor to let the fan run at full speed). I originally allocated 3 relays per fan in order to control the speed but I haven't connected them up (until I determine how to confidently keep the relays mutually exclusive).

I've tried setting each of the 3 switches to a preset level (eg. 33, 66, 100) and then set the 3 relays to be activated based on these thresholds. This kind of works in that if the fan was on full speed and the user presses button #2, the LED on button #1 would turn off (correctly) and button #2 would turn on (correctly). The problem occurs when I try to turn the fan off ie. I kind of need a 4th button with a preset level of 0% but I've only got 3 buttons!. Does anyone have any good ideas on how to get this to work ?

I recently bought a sweep fan relay to try - this would alleviate the problem with keeping the 3 relays isolated. However, I'm still stuck in the same situation - how to control the fan using 3 buttons. Any ideas ?

Given that I already own enough relays (3 per fan), I'd prefer to not buy a bucket load of sweep fan relays. In saying that though, I understand that the sweep fan relay also provides the benefit of starting the fan at full speed for X seconds before it switches in the appropriate speed capacitor.

Did I mention that I have a Ness M1Gold with the CBUS interface ? I haven't tried setting up any 'rules' to control the fans - but I will probably need to resort to this if it can't be done natively via the CBUS equipment.

Thanks in advance for any input you can provide.

 

I guess the real question should have been:
Any ideas on how to configure the system to use 3 buttons instead of 4 ?

I guess I could always just have 2 speeds (using 3 buttons) instead of 3 speeds (using 4 buttons), but I don't really want to allocate a button just to turn the fan off.

IDEA:

• Setup each of the three buttons to preset levels 33, 66, 100.
• Have my Ness M1G monitor the buttons and if the current level for the group matches the preset level produced by the button then send another CBUS command to set the level to 0% (to turn the fan off).
• I don't know if this is feasible with the Ness M1G.

Any other suggestions ?

 

Set the preset levels for the short release function, and an OFF commnad for a long press function. A short press will set the speed and a long press on any button turn the fan off.

 

Do you have any c-bus logic devices or are the 'smarts' handled by M1?

 

No I don't have any CBUS logic devices. I've only just recently installed the Ness M1 and haven't yet created any rules related to the lights.

I like the suggestion made by Ashley regarding the short release and long press options for each button. I'll try it out tonight to see if it's suitable.

 

The M1 work's fine for simple logic but the rule based engine is a very limited in what you can do without getting very messy, particulary when you want to start doing sequential stuff. Just remember to load all 256 lighting groups (not just the ones you are using) or it gets itself in a bit of a knot. Personally I would never install a C-Bus system without a logic engine these days.

 

If you want to have the 3 realy channels acting in a mutually exclusive fashion then you can condider the relay channel interlocking feature of the relay units.

In your specific case you would set the number of interlocked channels to 3 and use relay channels 1, 2 and 3 of the relay unit as speeds low, medium and high respectively. If the 3 relay channels are assigned the same group address then the channel with the highest turn-on threshold (that is below the current group address level) will be the relay channel that will be on; the other interlocked channels will be off. The main down-side of this approach is that you can only use the interlocking feature once on a given relay unit. You also don't get status indication on the switch as to the currently-selected speed, just off/on status.