DXL360S, dual-axis digital inclinometer

This review will be written in a style that’s rather unusual for me. At the very least, it’ll be short; at most, it won’t include the usual teardown of the item being reviewed. But there’s a reason for that, and I’ll try to explain as I go.

This device goes by several names, for example: inclinometer, protractor, digital protractor, two-axis level.
I think “inclinometer” or “two-axis level” are the most accurate terms.

As usual, let’s start with a few photos of the packaging.
The box is a universal one for two versions of the device, each available in two variants.


Inside is a tray made of expanded polyethylene. The device and everything else fit very snugly, which is a good thing when it’s being shipped from far away.


The package contents are modest, though I’m not even sure what else could be included.
1. DXL360S digital inclinometer
2. Charger
3. USB-miniUSB cable
4. Manual and warranty card.


The manual is in two languages, English and Chinese. For convenience, here’s the PDF version of the manual.


And here are the stated specifications. I should mention that there are two main versions of the device, the DXL360 and DXL360 V2; this review covers the newer version.
In addition, each version comes in three variants: DXL360, DXL360S, and DXL360SC. I’ll say a few words about those too.

First, the features.
1) DXL360S: Accuracy ±0.05°, resolution 0.01°
DXL360: ±0.1°, resolution 0.02°
2) One- or two-axis measurement, with automatic switching and a convenient display readout
3) Battery-powered
4) V-shaped notch and metal housing for easier positioning not only on flat surfaces, but also on pipes.
5) Magnets on 5 sides
6) Audible alert
7) Any-angle measurement, DXL360S only
8) USB connection to a computer (DXL360S only); the DXL360 requires a USB
adapter.

Specifications
Accuracy: DXL360S:
0 to 20°: ± (0.05°)
20 to 70°: ± (0.1°)
70 to 90°: ± (0.05°)
*After calibration

Measurement range: One axis: 360°, two axes: ±40°
Resolution: DXL360S: 0.01°
Any Angle Measurement 0.5°
Gyro Rotation Speed: <50°/s
Information update time: <0.4 second
Sound level: 60dB @ 30cm
Zero drift per °C: 0.0058° (typical)
Operating temperature: 0 to 50°C
Display: Backlit monochrome LCD
Power source: 3.7V Li-Polymer battery
Charging: 5V 500mA Mini type-B USB port
Power consumption: standby mode: 10uA, operating mode: 20mA.
Standby time: 4000 h
Normal operating time: 40 h
Dimensions (in mm): 70(L) x 70(W) x 23(H)
Magnetic Base: affix at 4 corner
Magnetic Force: N48
Weight: 120gram

As I mentioned above, the package includes a USB-microUSB cable. It’s fairly flexible and about 70cm long.
A charger is also included—or, more precisely, a power supply with a charging-complete indicator.
Current up to 1000mA, voltage 5 V, European plug; it fits securely in the socket.


In this case, the power supply was the only thing I dared to open without worrying about breaking something.


The power supply is very cheap. Besides the power supply itself, the board has an output-current monitoring circuit and a two-color LED (charging/charge complete).


The feedback circuit uses a zener diode rather than a TL431; there’s a resistor in place of a fuse, and a self-oscillating circuit instead of a PWM controller. At least they used the right interference-suppression capacitor. The board’s soldering is mediocre.


The device is quite compact: a solid block measuring 70x70 mm and 28mm thick.


When switched on, it displays the firmware version and device model; when switched off, it says “Thanks Goodbye.” :)


On the right side are a microUSB socket and a hole for the buzzer. The device beeps quite loudly and sharply, so I think it’ll be noticeable even with a lot of background noise.
As I mentioned above, they used mini USB here rather than the more common micro USB. On the one hand, this is a downside, since it makes the cable harder to find. On the other hand, it doesn't matter much because the device has a long battery life, and miniUSB is sturdier.


There are a couple of threaded holes on the back. I assume they're for mounting the device permanently on equipment or a rail when the magnetic mount might not be enough.


As mentioned in the features, the ends of the housing have V-shaped cutouts to hold the device more securely on round objects, such as pipes.
The magnets inside are quite powerful. I've only had the device slide down a vertical pipe once, but the pipe was painted and wet. It sticks to flat surfaces without any trouble.


As I said at the very beginning of the review, I won't be taking it apart, and there are reasons for that.
First, I tried to peel off the front panel, but the tape holding it in place is very good quality and tears rather than simply peeling off. I was already thinking I could stick it back on with different tape, but something else stopped me.
Then I thought, well, I could remove the circuit board and screw it back in, but the factory calibration depends on the board's position in the housing, and I'd have to say goodbye to it. I really didn't want to do that, since the device is calibrated quite well at the factory.

In the end, after my experiments, one corner of the front panel still won't stick back down :)


Fortunately, there's a popular website where devices like this have been discussed quite extensively, and there are photos of the inside. This one is from a completely different manufacturer, but the basic idea is clear.


The same thread also suggests an alternative: using a smartphone with a separate app, which is free.


I'll also show one way people use this device in their work.


A little about the device's front panel. It's made of fairly soft plastic, so I don't recommend removing the protective film right away.
The display is a dot-matrix LCD, and in my opinion it's too bright. The image in the photos below won't be very good, but that's a limitation of the camera, not the device. I haven't noticed any real problems during use, except that I might turn the brightness down a little.

Since the display is a matrix, the device automatically rotates the image to match its orientation. I'll show the vertical display later. In horizontal mode, the screen shows both axes at once, as well as the diagonal tilt and a bubble-level simulator.

There are four buttons along the bottom. Here's what they do:
1. Power on/off. In Menu mode, this means "cancel".
2. Zero — switches to relative measurement mode. Press and hold to turn the sound on or off (indicated on the display).
3. Hold — freezes the readings on the display (the unit symbol flashes when activated). Press and hold to switch units.
4. Angle — switches between inclinometer and gyroscope modes. Press and hold to open the settings menu.

The buttons are quite stiff and click distinctly when pressed.


The device menu has five items:
1. The list itself.
2. Restore the factory calibration.
3. Calibrate the axes. I tried it and ended up with the same result as the factory settings :)
4. Quite a few sound settings, where you can set limits for each axis and choose whether the sound activates when the reading goes outside the limits or when it enters them. This can be very handy. But at home, I turned the sound off completely because it can get really annoying.
5. Auto power-off mode: after 30 minutes, or never. By default, it turns off after 30 minutes.
6. Gyroscope calibration.


The device supports four measurement modes:
1. Percentage deviation from zero.
2. Relative measurement mode (zeroed with the ZERO button), indicated by a triangle at the top.
3. Tilt angle in degrees.
4. Deviation in mm/m. The device displays the tilt in millimeters per meter of axis length.


Gyroscope mode. To use it, stand the device upright, press the right-hand button, and wait for it to complete its automatic calibration (about 2 seconds).
After that, the device displays the angle of rotation around the vertical axis. Two full turns give a reading of 720 degrees, though the maximum is 999.9. According to the manual, the rotation speed should not exceed 50 degrees per second, but I tried turning it noticeably faster and had no problems.


Testing the device is both easy and difficult. It's difficult because I don't have any reference-level horizontal or vertical surfaces. And simply because calibration is fairly straightforward in principle, and it’s hard to get it wrong.
A simple example: checking an ordinary bubble level. Place it in one position and note where the bubble sits, then rotate it 180 degrees around its axis and check the bubble again. The true position is the midpoint between the two readings.

That’s why the first test was similar to the one described above.
First, I placed the level on the table and zeroed the reading, so the device would think it was sitting on a perfectly horizontal surface. Then I placed it in the other three positions and compared the readings.

The specifications claim +/- 0.05 degrees; I got 0.02–0.04. It’s worth noting, though, that the last digit takes a few seconds to settle and can fluctuate by up to 0.02 degrees while it does. You can see roughly the same thing with any digital measuring instrument, such as a multimeter, which even specifies how many digits are allowed to vary.
And since the device is sensitive, even how smooth the surface is makes a difference.


For more accurate readings, it’s better to use a straightedge, a level, or a long ruler.
That way, small surface irregularities are averaged out.


The second test was measuring the height of the incline—I’m not sure what the proper name for this is, so apologies.
I took a one-meter level, placed it on the floor, zeroed the reading, then raised one end to an arbitrary height and measured it with a ruler and an angle gauge.
By and large, the readings matched, with a small error caused by the design of my level. It has plastic inserts on the sides with a slight bevel, so the readings differ a little.
The angle gauge showed 76.3 mm; the ruler showed 76 mm.


Since the device can measure both relative and absolute angles, and remembers the last mode used, you need to be very careful when using it.
After switching it on, you might not notice that relative measurement mode is still enabled and end up with “weather on Mars,” as I did when measuring the floor slope.
Don’t pay attention to the bubble level; it’s just for looks. I use this level as a straightedge. I have another one for actual leveling, but it rarely stays at home :)


The ability to measure two axes at once is a big help. With single-axis measurements, you have to keep turning the level back and forth; here, you can immediately see the direction of the slope, even diagonally.

A note about the display. All the measurement photos (except for the gyroscope) show the “virtual bubble.” It’s only really useful in two-axis mode.
In two-axis mode, the bubble moves fairly smoothly across the screen pixel by pixel. In single-axis mode, it only has three positions, and sometimes you can even see 00.00 while the bubble isn’t centered. At 00.01, it’s guaranteed to be at one extreme.


To demonstrate how it can be used, I placed the angle gauge on the windowsill. The installers did the left side, and my wife and I did the right. The left section of the sill is about a meter long; the right one is almost 6 meters.
The point is that the left side slopes toward the window, while the right side slopes toward the room, which is more correct. The recommended slope is considerably steeper, around 1–2 degrees, but I didn’t know that when it was installed :(


Power consumption and charging.
I measured the device’s power consumption indirectly. The manual specifies a current draw of 20 mA. I measured the current from the power supply while charging, with the device switched on and off, and got 30–40 mA. But this method is only a rough estimate, so all I can say is that 20 mA seems entirely plausible—30 mA at most.

As for battery life, honestly, I got tired of trying to run it down. It sat switched on on my desk all day and didn’t even show half the charge used. It started at 100%, and that’s where it stayed. So battery life is more than excellent. And since you’ll usually use this device by switching it on, taking a measurement or two, and switching it off, I think it’ll last a long time.


Now I’ll try to sum things up briefly.
Pros
Two axes
Gyroscope
Flexible audible alarm settings
Large display with auto-rotation and backlight
Rechargeable battery
Sturdy, convenient design
Good accuracy

Cons
The case is not really designed to be taken apart
The MiniUSB connector is not very common

My opinion: this is certainly a fairly specialized device. It can be partly replaced by simpler, cheaper options such as an angle gauge or protractor, as well as an ordinary level, but it’s more convenient to use than any of them.
I liked its solid, sturdy construction and the convenient display. In normal use, you usually don’t even need to press anything; most things happen automatically.
The rechargeable battery is another welcome feature, and I think anyone who uses it a lot for work will appreciate it. If you only use it occasionally, there isn't much difference.

As for accuracy and price: when I chose this instrument, the manager also suggested a slightly simplified version — DXL360, which measures with an accuracy/resolution of ±0.1°/0.02°, compared with ±0.05°/0.01° for the model reviewed here, and costs $10 less. If I were buying one now, I’d probably choose the DXL360, since 0.1° is still quite good. There’s also a more accurate option, the TLL-90S, with ±0.005°/0.001° accuracy, but it costs three times as much, so it’s more of a professional-grade solution.

I didn’t count the theoretical option of connecting it to a computer as an advantage, because there’s a lot that’s unclear about it.
For starters, one source says the DXL360S connects via a USB-RS232 converter, and only the DXL360SC can be connected directly. Another source says the DXL360S can be connected directly.
In my case, connecting it to a computer produced an “unrecognized device” message, and it didn’t appear in Device Manager. I tried to figure it out by looking for software and drivers on the manufacturer’s website, but unfortunately, they’re not there. So I can’t count connectivity as a plus, since I couldn’t confirm it.

For the review, the manager gave me the coupon HXFDXL7, which brings the price down to $50.99 (free shipping). The coupon is valid until June 12.
By the way, if you’re interested in a coupon for the DXL360, I can ask for one.

That’s all. As usual, I’d be glad to hear your comments and suggestions for tests of this little instrument. I hope you found the review useful.