ldd help?

[Indusrty]

Can I hook multiple ldd 700 to the same dimming output on a coralux storm controler? I have three strings of blue on separate ldd700s and would like them to dim at the same rate and same time. Is this possible just using jumpers off the one output from the storm? Thanks.

 

[oreo57]

Can I hook multiple ldd 700 to the same dimming output on a coralux storm controler? I have three strings of blue on separate ldd700s and would like them to dim at the same rate and same time. Is this possible just using jumpers off the one output from the storm? Thanks.

From the spec sheet:
Max PWM current per pin:
40mA (Storm),
10mA (Storm X)

Seems oddly low.

Someone has the LDD PWM current draw numbers.. Can't find them now though. I recall around 10ma though

 

[Indusrty]

So I could run 3 on each output with a little buffer?

 

[dartier]

Someone has the LDD PWM current draw numbers.. Can't find them now though. I recall around 10ma though

The LDD current draw was quoted in the LDD thread on here. I think it was around 2ma/LDD, so if this is right than dimming 3 LDDs from a 10ma source should be fine.

I would just hook it up an try it. I am pretty sure you will be fine.

Dennis

 

[dartier]

Ok, I found the current draw as tested.

http://www.reefcentral.com/forums/showpost.php?p=21145416&postcount=738

To follow-up my previous measurements on the current draw of the LDD dimming circuit I enlisted the assistance from someone who knows more about electronics then me. It turns out my measurements were sort of correct, I just had a decimal point in the wrong place.

So, the actual measurements are:

100% duty cycle - 7.7uA
0% duty cycle - 53uA

Please note that these are micro amps rather than milli amps. So, in effect, we are never going to get close to exceeding the current limitations of the Arduino pins or board.

At a worst case of 53 uA at 0% duty cycle, you will not come remotely close to exceeding the 10ma limit. So driving 3 LDDs is no problem. You would top out at 188 LDDs from your single 10ma source (ignoring wiring losses which will be much more limiting than the LDDs requirement).

Dennis

 

[oreo57]

Ok, I found the current draw as tested.

http://www.reefcentral.com/forums/showpost.php?p=21145416&postcount=738



At a worst case of 53 uA at 0% duty cycle, you will not come remotely close to exceeding the 10ma limit. So driving 3 LDDs is no problem. You would top out at 188 LDDs from your single 10ma source (ignoring wiring losses which will be much more limiting than the LDDs requirement).

Dennis

Thanks for finding that..

 

[Indusrty]

Thank you very much for the help. The ldd thread is a lot of information to sift through.

 

[perkint]

It's quoted in the LDD data sheets (LDD-H and LDD-L) at 1mA max at quiesce, so again, should be more than fine

Tim