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Dimmabe LED Setup - Ramp up photoperiod or power?

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I am expecting plants on thursday and am trying to finalize my light settings.

I saw several threads that talked about finding the best photoperiod by starting a bit low and increasing until plants start to close up near the end of the photoperiod. Starting high can apparently lead to algae problems. I am trying to adapt these concepts to my dimmable.

Should I increase the LED power or increase the photoperiod to find the optimal light level?

I have two Kessil A360WE LED pendants on a 24" deep tank. That should be very high light intensity with great penetration at full power. They only dim down to about 40% of output (by Lux measurement out of water at 30"). Aside from human viewing time, are there any other factors I should consider in making this decision?
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I find it will always be pretty hard to totally avoid algae so allow myself some mistakes along that line. Planning can only get me so far and then I have to adapt it as things progress. And part of that progression will be how the tank and plants change as they grow so I encourage staying a bit flexible in the thinking. A plant that is 4" high at start may feel totally different when it gets taller and has something like a frying pan near the top?
I also like to see my plants so I adjust the light schedule to fit my viewing as long as it also fits for growing the plants. I have no qualms with going for a four hour lights on with time off while I'm less prone to be there and then another lights on period later in the day.
Tough for me to set out a firm schedule for things that are constantly growing/changing themselves. I just use simple timers to turn various light sections on so not much help on the ramping question.
 

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Discussion Starter · #3 ·
Oh, I got that I will need to make adjustments and that I will have algae problems. No illusions there, but I do need somewhere to start. The closer it is, the more likely my first batch of plants will survive. Fortunately, I can mostly work at home (grading exams and papers) for the next few weeks.

I checked the power of the lights using my phone and the power to LUX was linear. I wish I had a waterproof meter to confirm that it is more or less linear underwater. That is my main concern about ramping intensity I think.
 

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@PlantedRich conveys my thoughts exactly.

As the plants grow things are ever changing. The most important aspects that help me are light timers and dimmable lights. The timers let me be both exact and consistent from day to day. Once I sort out the duration (photo period) I can just forget about everything and let the timers do all the work. The dimmable function makes it easy to fine tune everything, I start out a new tank with the lights dimmed lower than I expect and then slowly increase them over days/weeks until I see negative effects (algae in most cases). Although as PlantedRich stated, it's usually always changing as your plants grow and plant-load changes. I guess you could always just run your lights lower, but to push that fine line between maximum growth and the negative effects of too much light, you're always tweaking things. Just my thoughts...

Presently all my tanks run on a single 7hr. photo period.
 

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Should I increase the LED power or increase the photoperiod to find the optimal light level?
first realize the 2 are related...at least to a certain degree..

1000 photons per hour @ 1 hour is equiv to 500 photons per hour @ 2 hour.

so either works for the most part..
Kessil only dims to 40% seems odd..Most report 10-15% is normal though not sure if they did measurements..

Since it is driven (assuming here a bit) w/ PWM photons should be fairly linear (not to vision but that is another story). Full on at 40%, full on at 50% of the time ect..
 

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Yeah Jeff, it really ticked me off when I tested it. I wanted the gentle ramp up and down to not bug the family with the sudden flash or darkness my reef tank had. At the 13% power setting the lights turn on, but the lux measured at 30" through air was 40% of the lux at 100% power. Life goes on.
not the only ones.. Problem w/ "industry standard" 0-10v dimming drivers..
 

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Can you elabote more? You have the most informative posts I read on TPT.

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This is easier:
Control type: 0-10V
0-10V is an analog lighting control protocol. Basically, a 0-10V control applies a voltage
between 0 and 10 volts DC to produce a varying intensity level. There are actually
two existing 0-10V standards. They are not compatible with each other, so it is essential
to understand which type is required. The original 0-10V control was used for controlling
theatrical lighting. A lighting console provides a separate 0-10V output for each dimming
channel that connects to the input to dimmer modules located in a remote panel. The
other 0-10V control method was developed for, and is used as, a standard means for
controlling fluorescent dimming ballasts.
It has now become popular for some drivers
used for LED lighting.
0-10V Basics
The two 0-10V control types are
current source
(a theatrical dimming standard) and
current sink
(a dimming ballast standard).
There is an IEC standard for current sink controls - Standard 60929 Annex E. The
standard requires that the ballast (or driver) provides full light output when the control
voltage is 10 Volts (or above). As the control voltage is reduced by the control, the light
level is reduced. At a control voltage of 1 volt, the ballast (driver) provides it’s minimum
light level. Any voltage less than 1 volt is defined as minimum. Some drivers' minimum
is off, while other drivers' minimum is the lowest light level of the driver. It is important to
understand what minimum is for a particular driver. For drivers that do not go to off at
minimum, a separate relay or switching device is required
.
http://www.lutron.com/en-us/education-training/documents/10v.pdf

I assume most of this goes back to when they controlled current other than duty cycle..

PWM dimming and esp. 5V PWM using 0-100% duty cycle LED drivers is, arguably I suppose superior to straight voltage control.
0-10V signals are used in other applications (such as sensor signals) and has been found "lacking" as well..
https://sensortech.wordpress.com/2010/06/22/analog-signals-0-to-10v-vs-4-20-ma/
When it comes to sensor interface signals, 0-10V is like vanilla ice cream or, if you prefer, a Chevy Cavalier. It’s nothing fancy, but it get’s the job done. It’s common, it’s straightforward, it’s easy to troubleshoot, and nearly every industrial controller on the planet will accept a 0-10V sensor signal. However, there are some downsides. All analog signals are susceptible to electrical interference, and a 0-10V signal is certainly no exception. Devices such as motors, relays, and “noisy” power supplies can induce voltages onto signal lines that can degrade the 0-10V sensor signal. Also, a 0-10V signal is susceptible to voltage drops caused by wire resistance, especially over long cable runs..... The same can not be said for a 0-10V sensor. Zero volts could mean zero position, or it could mean that your sensor has ceased to function.
It needs to fade away. ;)

Just for fun..
In theory, LEDs are easily and fully dimmable, because — unlike some other kinds of light sources — there’s nothing inherent in their makeup that would impede the dimming process. On top of that, LEDs typically maintain their efficacy when they’re dimmed, and sometimes even increase it — whereas incandescent sources become less efficacious when dimmed.
The LED Dimming Dilemma

http://www.meanwell.eu/ExclusivePDF/DIMMING-NOTE.pdf

Point is there is little excuse not to use 0% and sliding dimming in modern lights.. Problem is "compatibility" w/ 1st gen controllers like Apex (yea they won't like being called 1st gen) as compared to more current but limited functionality.
somewhat of a self perpetuating system..

Granted some of this is personal preference..
 

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Discussion Starter · #10 ·
For reference for anyone considering the Kessil and a controller. The manual dial on the fixture has essentially the same cutoff as the Apex and the cutoff is not affected by which type of outlet on the apex or wall you use to power the light. It looks great on the tank and I like the color of the tuna sun, but not as dimable as the AI fixtures.
 

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This is easier:.
http://www.lutron.com/en-us/education-training/documents/10v.pdf

I assume most of this goes back to when they controlled current other than duty cycle..

PWM dimming and esp. 5V PWM using 0-100% duty cycle LED drivers is, arguably I suppose superior to straight voltage control.
0-10V signals are used in other applications (such as sensor signals) and has been found "lacking" as well..
https://sensortech.wordpress.com/2010/06/22/analog-signals-0-to-10v-vs-4-20-ma/


It needs to fade away. ;)

Just for fun..

The LED Dimming Dilemma

http://www.meanwell.eu/ExclusivePDF/DIMMING-NOTE.pdf

Point is there is little excuse not to use 0% and sliding dimming in modern lights.. Problem is "compatibility" w/ 1st gen controllers like Apex (yea they won't like being called 1st gen) as compared to more current but limited functionality.
somewhat of a self perpetuating system..

Granted some of this is personal preference..
They are talking about 4-20 miliamp control for lighting. How does this control the light output, more specifically on LEDS? My understanding of this is null, as in non-existent, so the current contolls the PWM cycle?

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They are talking about 4-20 miliamp control for lighting. How does this control the light output, more specifically on LEDS? My understanding of this is null, as in non-existent, so the current contolls the PWM cycle?

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no that is for sensors..not lights..
Point was 0-10V is a standard for more than just light dimming but has its warts.
 

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no that is for sensors..not lights..
Point was 0-10V is a standard for more than just light dimming but has its warts.
Ah yes, you are correct. I had to reread everything again. Do you know where I can read about NEMA SSL-7 part A?

Edit: Google failed me, my previously linked article had no pertaining information also I removed it. I will keep looking.

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Discussion Starter · #14 ·
10 hour photoperiod and ramping intensity from 30% setting it is. The six profiles let it ramp through a sin model diurnal cycle in light intensity (brighter at noon). It wont matter now, but will be more noticeable as the max intensity goes up. Wish it really started from zero. Not quite sure whether to vary color at sunrise sunset given it starts straight at midday intensity.

Here are my programs for now

LED_Left (outlet)
Fallback OFF
Set OFF
If Time 11:00 to 21:00 Then ON
If Temp_S > 84.0 Then OFF
If FeedB 000 Then ON

LED_Right (outlet)
Fallback OFF
Set OFF
If Time 11:00 to 21:00 Then ON
If Temp_S > 84.0 Then OFF
If FeedB 000 Then ON

LED_Color (6_1) (variable speed port)
Fallback Off
Set Off
If Time 11:00 to 12:40 then C_Dawn
If Time 12:41 to 19:20 then C_Day
If Time 19:21 to 21:00 then C_Dusk
If FeedB 000 then C_Day

LED_Intensity (6_2)
Fallback Off
Set Off
If Time 11:00 to 12:40 then I_EarlyMorn
If Time 12:41 to 14:20 then I_MidMorn
If Time 14:21 to 16:00 then I_LateMorn
If Time 16:01 to 17:40 then I_EarlyAft
If Time 17:41 to 19:20 then I_MidAftProfiles
Profile Name: C_Dawn sunrise
Control Type: Ramp
Ramp time (minutes): 100 photoperiod /6
Start intensity: 100 aesthetics
End intensity: 40 aesthetics

Profile Name: C_Day daylight
Control Type: Ramp
Ramp time (minutes): 1 short
Start intensity: 40
End intensity: 40

Profile Name: C_Dusk (sunset)
Control Type: Ramp
Ramp time (minutes): 100
Start intensity: 40
End intensity: 100

==================================

Profile Name: I_EarlyMorning sunrise
Control Type: Ramp
Ramp time (minutes): 100 photoperiod /6
Start intensity: 13 minimum response
End intensity: 22 min + 0.5*range

Profile Name: I_MidMorning
Control Type: Ramp
Ramp time (minutes): 100
Start intensity: 22
End intensity: 28 min + 0.866*range

Profile Name: I_LateMorning
Control Type: Ramp
Ramp time (minutes): 100
Start intensity: 28
End intensity: 30 maximum response

Profile Name: I_EarlyAfternoon
Control Type: Ramp
Ramp time (minutes): 100
Start intensity: 30
End intensity: 28

Profile Name: I_MidAfternoon
Control Type: Ramp
Ramp time (minutes): 100
Start intensity: 28
End intensity: 22

Profile Name: I_LateAfternoon
Control Type: Ramp
Ramp time (minutes): 100
Start intensity: 22
End intensity: 13

Profile Name: I_View
Control Type: Ramp
Ramp time (minutes): 1
Start intensity: 15
End intensity: 15
If Time 19:21 to 21:00 then I_LateAft
If FeedB 000 then I_View
 

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Osmosis, if you can control each lamp individually, why not start one up and the let it ramp to full power as quickly as the control allows, then start the 2nd one at that time and when the 2nd lamp ramps up, leave both on for a while and then reverse the process. As a fisherman, I can attest that under the east bank the water is dark until the sun rises over the tree line and then the reverse happens to the west bank. So a sudden 30 or 40% may not be that unusual considering tropical freshwater plants are often surrounded by dense forest and plants may "see" sunlight more suddenly then gradually. Just a thought.
 

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Ah yes, you are correct. I had to reread everything again. Do you know where I can read about NEMA SSL-7 part A?

Edit: Google failed me, my previously linked article had no pertaining information also I removed it. I will keep looking.

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see from about pg5
http://aceee.org/files/proceedings/2016/data/papers/1_154.pdf

All that applies to TRIAC type dimmers and pulsing the AC lines..
Really won't (and shouldn't) apply for aquarium lights..
 
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