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Electronic Theatre Controls Inc

Reading the Compatibility Report

This guide aims to provide a simple explanation of everything likely to be found in a typical ETC Dimming Compatibility Report. Not every report has every section listed here;  however, the sections will always be presented in this order.

Product Overview

Manufacturer: Manufacturer of the tested luminaire/driver.

Model Number: The model ID of the luminaire/driver, like how you'd order it from a catalogue.

Device Type: Generally, what is this? If it's a lamp, we list what kind (A19, PAR38, etc.) If it's an identifiable driver powering an LED array, the driver will be listed, even if it's in a fixture. If it's a fixture with an unidentifiable driver (because it's potted and can't be seen, is an unlabeled circuit board, etc,) then it's listed as a fixture with integral electronics.

Dimming Type: The protocol used to dim the samples for the test.

Voltage: The input voltage for the samples to make them function - often 120V or 277V, but can vary.

Nominal Power: The number of watts the samples use, per the manufacturer.

Measured Power: How many watts the samples used, when measured.

Quantity: The number of samples which were used to conduct the test.

Other Notes: If there's anything generally unusual about a sample's performance, it will be listed here.

Transformer Information: Some low-voltage LEDs, like LED Tape and MR16 lamps, require use of a transformer. All the above details will be listed for the transformer used with the test.

Best ETC Performer: Which ETC dimmer these samples performed best on - a good rule of thumb if you're interested in a new system or a module upgrade.

Performance: A brief sentence describing the sample's fade performance and minimum stable brightness.

Testing Equipment: Testing equipment used to conduct the test, apart from the samples and dimmers mentioned.

Results Summary

This page, if included, gives a brief overview of performance on all tested dimmers. Much more detailed information can be found further into the report, but this page can provide a quick rule of thumb.

Dimmer (and module): The dimmer the samples were tested with.

Minimum Stable Brightness: The minimum light output (as a percentage of full brightness) where, under that amount, the light is visually unstable until turning off.

Fade Grade: A letter grade to quickly summarize the fade performance of the samples on this dimmer.

How to Interpret Dimming Performance Results

These pages give a few example cases of Brightness & Flicker Curve graphs (if generated for this report) and details how to read them. It's a good idea to review these examples (they're the same on every test report) to understand what the reports detail, since they contain a lot of information. The big notes to take away are -

- Black dots represent the output brightness (as a percentage of full brightness) at a control level.

- The gray, spiky lines represent shimmer, also known as visible instability; kind of like candle flicker, but not always that strong.

- The higher the shimmer lines, the more noticeable the output instability is.

- The wider the shimmer region (from top to bottom,) the more variable the shimmer was - this means sometimes it's more unstable than other times.

Individual Dimming System Test Results

Each dimming system the samples were tested with is listed in this section, with detailed performance characteristics.

Brightness and Flicker Curve Graph (if included): As defined in Page 3-4. Sometimes fixtures perform in a way which makes the resulting graphs inaccurate, so these can sometimes be excluded if deemed necessary.

Minimum Stable Brightness: The minimum light output (as a percentage of full brightness) where, under that amount, the light is visually unstable until turning off. If and when the output is visibly unstable is assessed by the testing engineer. Instability can range from "if you stare at the light, you can notice it waver a little," to "this is actively strobing and impossible to not notice." Depending on the application, some amount of instability can be acceptable, though what is acceptable must be determined by the users.

Fade Performance: In a few sentences, gives a description of how the samples appear while fading, and when turning on and off. These correspond closely to the Fade Grade descriptors in the Results Summary, but sometimes additional detail is necessary to accurately describe performance.

Dimmer Settings: The best settings found for use with the samples, which the test was conducted with.

Max Quantity per Circuit: The maximum number of this sample which can be put on one circuit of this dimmer type. This does not account for any sample mixing, and in some cases (like a low-voltage transformer powering a variable length of tape) no number can be given.

Inrush Current: Worst-case current draw of the samples on this circuit when turned on. This can sometimes restrict the Max Quantity per Circuit beyond the measured power draw and/or stated power draw of the samples.

Capacitive Effects (D20-style Dimmers Only): Lists whether capacitive effects negatively impacted the performance of the samples. If they did, but could be fixed with additional rack programming, the necessary settings are included here. Additional information can be found on the "Capactive Effects" page.

0-10V Measurements (0-10V Dimming Only): Measures voltage and current on the 0-10V lines, both at a control level of 1% and at 100%. This can impact the Max Quantity per Output.

Other notes: Any other notes about sample performance.

Capacitive Effects / Power Measurements

This page lists observed voltage and current waveforms of samples in operation, which determines the watts used. Measured wattage values can sometimes be higher or lower than what the manufacturer states, which can affect the number of lamps a circuit can support.

If the samples observed any capacitive effects with D20 dimming, that will be listed here. It's possible that SCR misfiring was only observed in Legacy systems, since they're less naturally resilient to such behavior. In some cases, SCR misfiring might not be fixable.

Inrush Testing (Forward Phase)

This page lists the worst-case inrush current draw and duration when the samples operate in forward phase dimming or switched applications. This applies to D20-style modules, relay modules like when used with 0-10V or DMX dimming, and ELV modules programmed to forward phase (which is unusual, but is sometimes necessary depending on the samples.) Inrush current can limit the number of fixtures allowed on a circuit, which is reflected in the Max Quantity Per Circuit of a dimmer.

Inrush Testing (Reverse Phase)

This page lists the worst-case inrush current draw and duration when the samples operate in reverse phase dimming. This applies to ELV modules and phase-adaptive modules during typical operation. Inrush current can limit the number of fixtures allowed on a circuit, which is reflected in the Max Quantity Per Circuit of a dimmer.

Voltage Distortion Testing

This page lists any observed voltage distortion of the samples in operation. Voltage distortion can only be an issue when dimming LEDs on D20-style dimmers, so this not a concern for ELV or phase-adaptive dimmers. However, it tends to get worse with additional fixtures on a circuit, and can seriously impact performance or lifespan of lights, so being aware of whether this is a probable concern is greatly helpful when intending to use D20 modules.

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