The Emisar D4S flashlights use a firmware named RampingIOS V3. (The Emisar D4, D1, and D1S all use RampingIOS V2.) There’s not really a manual; the only thing we get is the diagram on the right. It’s reasonably comprehensive, but there’s a fair amount of detail it merely summarizes, so I thought a textual manual would be nice.
The Emisar D4S only works when the head and tailcap are tightened fully. You can physically lock it out—prevent it from turning on accidentally—by simply loosening the tailcap a small amount. A quarter turn will do it.
Emisar lights are known for their ramping interfaces. Rather than have a small number of distinct brightness levels, they can vary their brightness anywhere between their lowest and highest levels, like a light on a dimmer. The D4S is in ramping mode by default, but it also has a stepped mode that can be configured to be closer to how non-ramping lights work.
Each mode—ramping and stepped—can have differently-configured brightness floors and ceilings.
The driver for the D4S has two different chipsets. At low brightness levels, a fairly-efficient but low-power chipset (called a 7135) is used. These lowest brightness levels are called the “regulated levels”. Each regulated level will always be the same brightness regardless of how much charge the battery has. Above a particular brightness level, the light switches over to a less-efficient but high-power chipset (called a FET). These levels are called “direct-drive”. The brightness of the direct-drive levels is directly related to the battery’s charge level; the more charged the battery, the brighter the levels. The light is at its most efficient, in terms of power used for every lumen generated, at the brightest regulated level. When the light is first powered by tightening the tailcap, it will default to this level.
At higher brightness levels, the light’s LEDs generate a lot of heat. If the light exceeds its configured maximum temperature, it will begin dimming itself automatically until the temperature drops below the allowed maximum.
The D4S has a set of cyan-colored auxiliary LEDs that can be on when the main LEDs are off. You can configure the behavior of the aux LEDs.
§ Basic Usage
The default mode for the light is ramping mode. Triple-pressing the button (3 clicks) while the light is on will toggle between ramping and stepped mode.
While the light is off, press and release the button (1 click) to turn it on. It will turn on at the last-used brightness level. (This is called “mode memory”.) Immediately after loosening and tightening the tailcap (or after changing the battery), the memorized level will be the light’s max regulated level.
When the light is on, 1 click will turn it off. The current brightness level will be memorized for future use. There’s a fraction of a second delay between pressing the button and the light actually turning off. That’s because of the way the light processes input; it’s waiting to make sure you’re only going to press the button once (since multiple presses will trigger other actions).
When the light is on, holding the button down will brighten the light. In ramping mode, the brightness will increase gradually ("ramping up"). In stepped mode, the light will jump through increasing brightness levels. If you press, release, and then hold the button, it will begin dimming. In ramping mode, the brightness will decrease gradually ("ramping down"). In stepped mode, the light will jump through decreasing brightness levels. While the light is changing, if you release the button and immediately hold it again, the direction (dimming or brightening) will switch.
In ramping mode, while the light is ramping, it’ll briefly blink off and on again at two different brightness levels: the maximum regulated level and the brightness ceiling.
While the light is off, double-pressing the button (2 clicks) will immediately jump to the brightness ceiling.
While the light is on, 2 clicks will jump to the maximum brightness level, regardless of the configured brightness ceiling. Another two clicks will go back to the previous brightness level.
While the light is off, if you hold the button the light will turn on at its lowest level. If you continue holding the button, the light will begin brightening from there.
# Configuration Menus
The light has several different configuration modes. Each of those modes works more or less the same way. The mode will have a series of menu items that it will go through. For each menu item, the light will first blink a number of times corresponding to the item number (first, second, etc.) After that, the light will begin fluttering on and off fairly quickly. While the light is fluttering, you can click the button a number of times; the light will count the number of button presses and use that number as its new configuration for that menu item. After a short period of time, the fluttering will stop and the light will move on to the next menu item. After the light has gone through all of the menu items, it will return to whatever mode it was in before entering the configuration mode.
If you don’t press the button during a particular menu item’s fluttering, that item will remain unchanged.
# Configuring the Basic Modes
While the light is on, 4 clicks will enter ramping or stepped configuration mode, depending on which mode the light was in before the 4 clicks.
For ramping mode, there are two menu options:
- Brightness floor (default 1/150)
- Brightness ceiling (default 150/150)
During the floor configuration, press the button equal to the number of ramping levels (out of 150) at which the floor should be. To set the lowest possible floor, click the button once.
The ceiling is configured similarly, but you press the button equal to the number of steps away from maximum brightness. To set the highest possible ceiling (at max brightness), click the button once.
For stepped mode, there are three menu options:
- Brightness floor (default 20/150)
- Brightness ceiling (default 120/150)
- Number of steps (default 7)
§ Other Modes
The other modes largely involve multiple clicks from off. Most of them are not generally needed for everyday use, but they supplement the light’s basic operations.
# BattCheck/TempCheck Modes
From off, 3 clicks will enter “BattCheck” mode, which blinks out the current battery voltage. First it blinks the number of volts, then it pauses, then it blinks out the tenths of volts. Thus, if the battery were at 3.5 volts, the light would blink three times, pause, then five times. For zeroes, it gives a very short blink.
A fully-charged lithium-ion battery is 4.2 volts. The light considers 2.8 volts to be an empty battery and won’t turn on if the battery is at or below 2.8 volts.
The voltage sequence will continue blinking until you turn off the light with a single click.
While the light is in BattCheck mode, 2 clicks will enter TempCheck mode. Instead of blinking out the battery voltage, the light will start blinking out its current temperature in degrees Celsius, first the tens digit then the units digit. Like BattCheck mode, the light will continue blinking out the temperature until you turn it off with a single click.
While the light is in TempCheck mode, 4 clicks will enter thermal configuration mode. See the thermal configuration mode documentation below for how that works.
# Tactical Mode
From off, 4 clicks will enter “tactical” or “momentary” mode. The light will flash once to show that it’s entered the mode. The auxiliary LEDs will turn off (if they were on). In tactical mode, the light will turn on at its memorized brightness for as long as the button is being held down. It will turn off as soon as the button is released.
There’s no button press combination that will exit tactical mode. To exit it, you will have to partially unscrew and retighten the tailcap.
# Lockout Mode
From off, 6 clicks will enter lockout mode. The light will flash twice to show that it’s entered the mode. There’s a separate aux LED mode for lockout mode, so you can tell whether the light is in lockout or not.
In lockout mode, pressing the button will turn on the light at its lowest brightness ("moonlight mode") for as long as the button is held down.
Another 6 clicks will exit lockout mode. The light will flash twice to show that it’s left the mode.
While in lockout mode, 3 clicks will cycle through the various settings for the aux LEDs in lockout mode. The four modes are, in order: low, high, blink (on high), and off. The default mode is blink.
Remember that loosening the tailcap a quarter turn will also lock out the light. Using the 6 clicks is called “electronic lockout”, while turning the tailcap is “physical lockout”.
# Aux LED Configuration
From off, 7 clicks will cycle to the next aux LED mode. The four modes are, in order: low, high, blink (on high), and off. The default mode is low.
# Beacon Mode
From off, 8 clicks will enter beacon mode. In beacon mode, the light will blink on and off every few seconds.
By default, the light will blink every two seconds. To change the timing, use 4 clicks while in beacon mode. The light will enter a one-item menu. During the flickering for input, press the button a number of times equal to the number of seconds between blinks.
1 click will exit beacon mode.
# Thermal Configuration Mode
From off, 10 clicks will enter thermal configuration mode.
The menu items here are:
- Current temperature (every click is one degree Celsius)
- Temperature ceiling (every click is one degree above 30°C)
The “current temperature” item can be used to adjust the calibration of the light’s temperature sensor. To use it, make sure the light has been off long enough that all of its components have cooled (or warmed) to the ambient temperature. Check the ambient temperature using a thermometer you trust. Go to thermal configuration mode, and enter the current temperature by clicking the button a number of times equal to the temperature in degrees Celsius. (If it’s 22°C, click the button 22 times.)
You can check the default calibration by entering TempCheck mode from a room-temperature light. The D4Ss are supposed to go through a temperature calibration at the factory, so hopefully most of them won’t need manual thermal calibration.
The temperature ceiling is simply the highest temperature the light should be allowed to reach. Once it hits its temperature ceiling, it will progressively dim itself until the temperature stabilizes below the ceiling. Note that the number of clicks in that menu option is added to 30 to reach the actual ceiling. (Thus, you can’t set a ceiling below 31°C.) The maximum allowed ceiling is 70°C.
The default temperature ceiling is 45°C.