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Low voltage control on a CTB16


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I was wondering if it would be possible to use channels 1-8 to control some SSRs so I can multiplex channels 9-16. If I remember correctly, channels 9-16 need 120 volts for the controls on the board. Is it possible to control a 5-12 VDC load off channels 1-8? Or must it be 5-12 VAC?

Thanks
Mike

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It has to be AC. This is because a triac is a high speed switch. It can turn off whenever (or close to that) but can only turn on at the zero-cross of the alternating current.

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That will not work. In my post above, I explained why that method, or any that involves converting to DC before the Triac, will not function. The the SSR is this case is a Triac, these devices rely on the zero-cross of the AC electricity. With DC there is no zero-cross. You would have to rectify it after the Triac, which would require a "wall-wart" or other transformer which would have a small delay turning on and a large delay turning off. The use of a 120vAC to turn on a DC output relay would be the best way to deal with this. The other method is to use one of the DC cards from D-Light. However, these will not work after the conversion to LOR II, if it ever happens.

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The external SSRs I intend to install are for multiplexing and therefore would only need to be on or off. In this case I don't need to worry about zero cross. That is why im 99.9% it will work.

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Mike Montgomery wrote:

I was wondering if it would be possible to use channels 1-8 to control some SSRs so I can multiplex channels 9-16. If I remember correctly, channels 9-16 need 120 volts for the controls on the board. Is it possible to control a 5-12 VDC load off channels 1-8? Or must it be 5-12 VAC?

Thanks
Mike


I don't remember, but do you have some old dasher chips ?

You could use those connected to 5volt SSR or even transistors for your multiplexing idea?

LOR "drives" the old dasher chips.

Just thinking.

Vic
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Yes I do have several old dasher boards however that will require an additional cat5 run and the length is significant in this case.

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I finally had a chance to run some tests and this will work just fine. I'm using a 12 volt wall wart as my power supply. Coming off the board's 1-8 channels I have 8 SSRs. They are DC controlled so there is a bridge rectifier on each as well as a 22k resistor so that the board "sees" enough load to switch on/off. Each of these SSRs controls the neutral for a bank of 8 channels, the hots come from channels 9-16. This gives me a total of 64 channels using one 16 channel board! And the wierdest part.... I tried this just switching the SSR connected to an external load before making it switch the neutral, and dimming works fine even though I'm converting the AC to DC! And the external SSR I'm using is zero cross NOT random!

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Mike,

Very interesting but a bit over my head. I was wondering if you could post a wiring schematic or drawing of what your are doing. I'm really quite interested in this.

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Programming really shouldn't be that bad assuming all 64 channels were used for like objects. For example, I plan to do 8 yard arches with 8 channels each. So in the sequence editor, I have 8 rows for what the arches are "doing" and then another 8 rows used only to specify what arch(es) is(are) presently "doing" whatever I specified. It's kind of confusing to explain but it makes sense in my head. lol

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Yes seems OK for some stuff and could save alot of cash! I was thinking maybe for LED strobes flashing randomly. Now I wounder if you could reverces the AC on one side of the board and do it with out the relays. I will have to look at this, But yes dimming should work as long as one side has the triac's and the other with the SSR just stays on for the full 60Hz cycle so the path is complet when ever the triac turns on. AI

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Pretty Neat!

Did you take any video of the lights? I sounds like you are still limited to a maximum of 8 objects at a time but with 8 options for each object. Very interesting. I hope that you can post a clip of what you did with that choreographic challenge.

Ed

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When Multiplexing you should only use one of 64 outputs at a time. If it runs fast enough then it seems like there are more than one on at a time, but LOR is not that fast. However, as stated, you could control any of 8 outputs in a row for 1 of 8 columns at a time, but here again, there can only be one column on at a time. Using it for LED strobes would be fine because you would never want them all on at the same time and randomness is good. AI

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  • 2 weeks later...
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Can a transformer be used with the traics on the LOR board? The transformer output w/ full wave bridge will go to a 12 volt LED rope light decoration.

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lonewolvie wrote:

Can a transformer be used with the traics on the LOR board? The transformer output w/ full wave bridge will go to a 12 volt LED rope light decoration.

Probably, But you may need and extra load to get the triac to switch properly and would have to run full on, no dimming. AI
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lonewolvie wrote:

Can a transformer be used with the traics on the LOR board? The transformer output w/ full wave bridge will go to a 12 volt LED rope light decoration.



Hi lonewolvie,

Are you meaning to feed the LOR board from the output of your 12v ac transformer? If so, then I guess that you are aware that this 12v ac can ONLY be applied to the channel 1 to 8 input i.e. the left hand input of a CTB16 with the two links between inputs REMOVED.


Just a heads-up

Martin
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lonewolvie wrote:

I was going to use 1 channel and connect a transformer to it to power the 12 volt LED's


OK. We're getting off-topic here so won't prolong the discussion. Just be aware that rapidly switching the supply to a transformer is not a good idea, most don't like it too much. Also, as AI says.......no dimming, just straight on or off.

Martin
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lonewolvie wrote:

Can a transformer be used with the traics on the LOR board? The transformer output w/ full wave bridge will go to a 12 volt LED rope light decoration.


In Australia, most outside light strings are transformer coupled for safety, (240V AC supply). I've been running LOR for 2 years now switching the 240V supply to transformers with no problems. Dimming also works in most cases.

see http://planetchristmas.mywowbb.com/forum25/4097.html

Geoff
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