How does Diurnal Light Setting Work?

[mjreefs]

First, I'd like to thank @robsworld78 for the awesome support on my robo-tank and reef-pi related questions. Thank you very much for the patience in answering my queries!

To my question, currently I have a Nicrew Hyperreef 150 controlled by my reef-pi. What I want to do is the following:
9am to 10am ramp up to peak light settings
10am to 6pm stay at peak light settings
6pm to 7pm ramp down from peak light settings

Rob initially suggested to have 3 settings, but unfortunately, my lights got extremely wonky and is having a lot of flickering (stays up for a few seconds, then suddenly turns off, then it would go on after another few seconds)

I have been reading about the "diurnal" setting which is supposed to simulate natural ramp-up and ramp-down then stay at peak hours for most of the time. Unfortunately, I have not seen any definitive how-to's on that. It only has "Min," "Max," "Start Time," and "End Time" as its parameters and there's really not much else info on how it works in the Reef-Pi User Manual (at least on the copy that I have). Any ideas?

Thank you!

 

[robsworld78]

First, I'd like to thank @robsworld78 for the awesome support on my robo-tank and reef-pi related questions. Thank you very much for the patience in answering my queries!

To my question, currently I have a Nicrew Hyperreef 150 controlled by my reef-pi. What I want to do is the following:
9am to 10am ramp up to peak light settings
10am to 6pm stay at peak light settings
6pm to 7pm ramp down from peak light settings

Rob initially suggested to have 3 settings, but unfortunately, my lights got extremely wonky and is having a lot of flickering (stays up for a few seconds, then suddenly turns off, then it would go on after another few seconds)

I have been reading about the "diurnal" setting which is supposed to simulate natural ramp-up and ramp-down then stay at peak hours for most of the time. Unfortunately, I have not seen any definitive how-to's on that. It only has "Min," "Max," "Start Time," and "End Time" as its parameters and there's really not much else info on how it works in the Reef-Pi User Manual (at least on the copy that I have). Any ideas?

Thank you!

Hi @mjreefs, no problem, always happy to help just sometimes I wish I was more helpful. Did you manage to get this figured out, based on our last message I think maybe you did?

 

[TheStaches]

@mjreefs I'm in a similar boat with my setup, RoboTank controlling dual Nicrew HyperReef 100.

Like we both found there's not a lot of documentation around the diurnal settings. If they are still relevant Here are the old docs to the light module that references this mode.

Min/Max will be the overall intensity any setting will apply.

Based on the screenshots in the docs, it looks like the start/end times will be the total light cycle with a 1hour ramp up/down.

While not as fluid, I have achieved a similar ramping approach with the Interval setting. This is for the blue channel set to a max intensity of 90% with a total light period of 12 hours.

 

[mjreefs]

Hi @mjreefs, no problem, always happy to help just sometimes I wish I was more helpful. Did you manage to get this figured out, based on our last message I think maybe you did?

@mjreefs I'm in a similar boat with my setup, RoboTank controlling dual Nicrew HyperReef 100.

Like we both found there's not a lot of documentation around the diurnal settings. If they are still relevant Here are the old docs to the light module that references this mode.

Min/Max will be the overall intensity any setting will apply.

Based on the screenshots in the docs, it looks like the start/end times will be the total light cycle with a 1hour ramp up/down.

While not as fluid, I have achieved a similar ramping approach with the Interval setting. This is for the blue channel set to a max intensity of 90% with a total light period of 12 hours.

Yes @robsworld78 , I'm currently using something similar to @TheStaches setup: using the "Interval" setup but instead of having it on a 1-hour ramp up and 1 hour ramp down, I ended up with a 2 hour ramp up and 2 hour ramp down. And yes, not the best, but hoping someone could chime in with the "Diurnal" settings and it might be a better option. The advantage of the "Interval" setup is I can have the Nicrew be at some "moonlight" (very low blues, I think just 7%, because any lower and the lights will suddenly go off) until 10pm then completely shut off until the next day.

 

[Sral]

Well, the diurnal works exponential, as far as I could see from my limited test. So very slow and smooth in the beginning (I was using the PCA9685) and speeding up somewhat realistically towards the actual sunrise. The time you enter as start and end are the actual times that the light will start from the minimum and go back to the minimum level as far as I can see. Maximum is self explanatory I believe.

Downsides I can see:
- One can't control the duration of the ramp-up and ramp-down as far as I can see. So if you want scandinavian or canadian sunrise- and sunset ramps I believe you will be out of luck for now ^^
- One can't directly enter a moonlight phase into the profile. You would have to stitch that together using timers (and maybe macros, if I'm not mistaken) by switching the day-diurnal profile off during the night and switching the night-profile on and vice versa. Seems slightly inconvenient currently, but I think @Ranjib is aware of that.

 

[mjreefs]

Well, the diurnal works exponential, as far as I could see from my limited test. So very slow and smooth in the beginning (I was using the PCA9685) and speeding up somewhat realistically towards the actual sunrise. The time you enter as start and end are the actual times that the light will start from the minimum and go back to the minimum level as far as I can see. Maximum is self explanatory I believe.

Downsides I can see:
- One can't control the duration of the ramp-up and ramp-down as far as I can see. So if you want scandinavian or canadian sunrise- and sunset ramps I believe you will be out of luck for now ^^
- One can't directly enter a moonlight phase into the profile. You would have to stitch that together using timers (and maybe macros, if I'm not mistaken) by switching the day-diurnal profile off during the night and switching the night-profile on and vice versa. Seems slightly inconvenient currently, but I think @Ranjib is aware of that.

Do you have an example, say, if I set it from 09:00 to 18:00: when would it ramp up? When would it reach peak lighting (maximum value)? When would it ramp down? When would it reach the minimum value?

 

[Sral]

Alright, I had a look at the code for the PWM-profiles on github and diurnal works with a cosine to the power of 3. The profile looks like this for different min/max settings:

The diurnal profile is at the minimum value outside the start and end times. In between the Start and End Time it ramps up and down.
At exactly the start time (denoted 0) it starts ramping up from the minimum, to the maximum. This takes about 1/5 or 20% of the time interval between Start and End. After about 1/10 or 10% of the interval the light is in the middle between minimum and maximum value ( in the plot: (80%+10%)/2 = 50% )
The same thing happends towards the end, at about 4/5 or 80% of the interval between start and end the light starts ramping down. It will have fallen half the way towards the minimum at about 9/10, or 90% of the interval between Start and End. At exactly the End time it will reach the minimum again.

Practical Example:
I set my light to Minimum 0% and Maximum 80%, since my light is a bit too strong, between 08:00 and 16:00.
It will slowly start up at exactly 08:00, reaching 80% shortly past 9:30 (20% of 8 hours are about 1 hour 30 minutes).
A few minutes before 14:30 it will start ramping down, reaching 0% exactly 16:00.

Something I saw as well, which @Ranjib mentioned in another thread:
there is a light profile called "composite", which seems to stitch together different light profiles for their respective programmable interval. In my case I could use this to, for example, have a diurnal between 08:00 and 16:00 and afterwards run a much weaker lunar profile between 16:00 and 08:00.
It's not exposed in the GUI yet, put I'm hopefull that I can either set this manually or wait for the update.