Product Review: Aplisens LI-24ALW

I first encountered Aplisens during a visit to check a flow meter at a Brazilian sugar refinery. As I walked across the plant, I saw this yellow device that looked like a VEGA transmitter. When I got closer, I saw a different brand and decided to look the company up. Glad I did.

Today, the crew of Aplisens shows up for the very first time here at Visaya! If you’ve never heard of this one, then you need to take a look at its huge list of products! We’ll discuss the LI-24ALW temperature transmitter to find out how this device can fit in a new application.

Disclaimer: This product review examines only features, not performance. If you’ve used this device, feel free to share your experience in the comments.

Whatcha got there?

The LI-24ALW has a design that mostly follows industry standard, but I like the color! The housing opens in back to give you access to the power supply connectors and sensor inputs. It also opens in front to let you access the electronics and set up the device locally with push buttons. Yes, you need to open the housing to set up. The procedure looks simple, but the documentation doesn’t offer much help.

Anyway, the display has three areas, LCD1, LCD2, and LCD3. LCD1 shows you current output or percentage of the measurement range, LCD2 the process value, and LCD3 the temperature unit. LCD3 also shows alarms and the device menu during configuration.

LCDs Display Aplisens LI-24ALW
Courtesy of Aplisens

A big plus is the backlight. The market has a bunch of similar devices without backlights, and the LI-24ALW even allows you to turn it on or off! I like this feature.

The LI-24ALW has two housing material options, aluminum or stainless steel. Furthermore, you can install your sensor directly into the device or remotely. Remote sensor installs are rarer than you may think at this level, so it definitely counts as another plus.

The minus column has an entry that many similar devices share: protocol shortage. You get analog and HART and nothing more. If you want FOUNDATION Fieldbus or PROFIBUS PA, then you’re out of luck here.

What can it do?

The LI-24ALW outshines most of its peers with its input options. Most devices in this tier only have a single input that will take a limited range of sensors. However, Aplisens brings the flexibility you usually find in high-end devices down to the LI-24ALW. It can read resistance temperature detectors (RTDs), resistance, millivolts, and an incredible array of thermocouples – K, J, S, B, N, T, R, and E!

Aplisens LI-24ALW Application
Courtesy of Aplisens

Now, the accuracy depends on the sensor you choose. For instance, a Pt50 with a measuring range from -200 to 630 degrees Celsius will have a processing error of +-0.2. Or a thermocouple type J (Fe-Cu45Ni) with a measuring range from -210 to 1200 has a processing error of +-0.2 as well. You can check out the entire list here or in the manual.

Why should I care?

Because there’s more! The LI-24ALW has intrinsic safety and explosion proof certificates, so if you run a chemical plant, you can apply this device without issues. It also has a protection class of IP67, so you can install it in dusty areas or submerge it up to a meter deep. This class comes standard to most of these devices, though.

Display LI-24ALW
Courtesy of Aplisens

It also has alarms for your current level in a standard setup and a second option for NAMUR NE 89 guidelines, or you can customize it. However, you won’t get fancy self-diagnostics or advanced monitoring information here.


The LI-24ALW makes a surprisingly good option for a low-end device! It has great input range, local configuration, good display, and many approvals. While it lacks protocols, outputs, and fancy features, it may still help in your process.

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