I’m using meanwell HLG - 80H - 48 - B which gets stepped down to 24v at the beginning of a 24v lighting strip. Im tryinhg to dim it with a 0-10v lutron dimmer but it’s not working. We’re trying to figure out if if it’s the driver, the step down, or the dimmer that is the problem. Please advise.
Greetings,
which gets stepped down to 24v at the beginning of a 24v lighting strip.
It’s unclear what the intended meaning is here, both at the “gets stepped down to” and “24v lighting strip” points.
The compliance range of the HLG-80H-48xxxx products is roughly 29~48V. The forward voltage of the driven load must remain within that range at all times and under all conditions in order for the device to function normally, including dimming behaviors. If you’re using a separate device after the HLG-xxxxx to re-convert its output, control of the dimming function would need to be performed using that device, rather than the HLG.
If by “24V lighting strip” you’re speaking of the common cut-to-length flexible sort (as opposed to a rigid device having a fixed configuration) the HLGxxxx series devices would not be an appropriate selection. The flexible cut-to-length strips require a variable-voltage supply for linear dimming, and devices of that sort that are compatible with 0~10v dimming aren’t especially common, to my perception.
Hi Rick,
Thank you for your prompt reply, I appreciate the help. The reason we used the 48v driver was due to the distance from the fixture to avoid voltage drop.
The “step down” was a transformer similar to this: LINK
We originally used the Meanwell LRS-450-24 to test the fixture, and the dimming function worked. You are correct this is a common cut-to-length flexible strip, specifically Blaze 24v: LINK
It seems if HLGxxxx does not provide variable-voltage supply this may be the issue. Can you recommend a driver that is compatible with 0-10v dimming?
We’re also exploring the possibility of PWM dimming since the Blaze LED strip allows for this method as well. Would this work with the HLGxxxx driver?
A few points of note:
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Your “step down” device would perhaps more properly be described as a “DC-DC converter” than a “transformer” insofar as the latter term carries strong connotations of a device that converts an AC input to an AC output.
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DC-DC converters of that sort are aimed at producing a constant-voltage output regardless of variation in input voltage provided. Trying to dim an LED string on the output by making the input voltage dance is not going to work well.
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The LRS-450-24 does not have a dimming function; it has an output adjust function that permits tweaks within a range of approximately -5%~+10% of the nominal 24V.
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The light output of a flexible strip of your sort is proportional not to the input voltage (Vin), but rather something like (Vin-18V). Tweaking the input between -5% and +10% of nominal will therefore produce a noticeable and well-controlled dimming effect, but sweeping the applied voltage from 0 to 100% of nominal will yield no light output over the vast majority of that adjustment range, and a very “jumpy” adjustment at the high end.
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That mismatch of adjustment ranges is why there aren’t many constant-voltage LED drivers that do linear dimming. One has to read the fine print in between the lines to identify them, but there are devices such as the PWM-90-24 that will take a 0~10v signal and generate a pulse-modulated output.
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In cases where the output strip is of fixed/non-adjustable length, selecting a constant-current driver of appropriate output current and compliance voltage ratings is an option that can compensate for losses in supply cabling. The disadvantage of this approach however, is that failure of any given LED segment will increase the stress on those remaining, and ultimately lead to a cascading failure effect.