Product Review: OleumTech Temperature Transmitter

I loved working on temperature projects because they use a principle that takes wireless communication well, and I’m always pushing wireless. Sometimes a customer prefers an old solution, but I’ve worked many projects that wouldn’t have existed if not for wireless.

You can find all kinds of wireless temperature solutions out there. We have several product reviews already, plus a list of seven wireless devices you must know. However, the market has bunches more, and today’s company brings an impressive solution with only a few cons.

Let’s say hi to the crew from OleumTech in the company’s first product review on Visaya! Today, we’ll go over the temperature transmitters. You know I usually specify a model, but I couldn’t here. You’ll see why shortly. Come on down!

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 wireless temperature transmitters from OleumTech take the traditional shape of a field transmitter with an external wireless antenna. But before we go any farther, let’s get the portfolio thing out of the way. OT has specific models for different sensors or display options. I’m not too keen on this. Other vendors offer these features as options in the order codes, making life much easier!

Courtesy of OleumTech

Anyway, in the OleumTech world, if you want a temperature transmitter with an integrated local display, then you go for the RT1. So far, so good. But if you want an external RTD sensor with a local display, then you need an RT2. But wait, there’s more! If you remove the display and keep the external RTD sensor, you get an RTM! See? Not in love with this approach, but hey, different strokes and all that.

In general, the device has a traditional design, and the simple local LCD display has 16 x 2 lines. It’ll show you the process variables, diagnostics, wireless signals, and local configuration. Four buttons let you navigate the device’s menu and set up the transmitter without a handheld.

The device communicates with the control system wirelessly, using a gateway to receive data from the field devices. It powers up with an internal 3.6-volt lithium battery which can squeeze out 7 years of juice. Of course, many factors can affect the battery life, so you may get less than that.

What can it do?

OleumTech’s different transmitters can connect two, three, or four wires to your resistance temperature detector (RTD) sensors. The company also has a model that only handles type-K thermocouples, which limits your options a bit.

Anyway, if you decide to use the RT1, then you can use RTDs between 2 and 18 inches in size, and it’ll support temps from -55 to 260 degrees Celsius. The RT2, for external RTDs, can read any range of temperature and type of RTD sensors. The TC1 (with display) and TC (without) support type-K thermocouples, and the temperature range will depend on the sensor.

Temperature transmitters OleumTech
Courtesy of OleumTech

You can configure the device on the local display if you choose a local display or through an RS232 port using the BreeZ software for PC. Yup, no HART here, just proprietary protocol – and a proprietary network too, called the OTC sensor network. I’m not a fan of proprietary stuff, so color me unimpressed.

Speaking of communication, you can choose a frequency between 900 megahertz (MHz) and 2.4 gigahertz (GHz). The best choice will depend on your application, as always. For instance, in a short range, the 2.4 GHz band has advantages like a  smaller antenna. But for long distances, the 900MHz has a greater wireless range – nearly 10 times more, according to OleumTech!

Why should I care?

First, OleumTech has a wide range of devices for different applications. Second, you can use the RTD devices in all processes where you use RTDs. Unfortunately, the thermocouple version only accepts K, dragging down the whole show. Plenty of other brands have simple devices that’ll use all kinds of RTDs and thermocouples. True story!

On the up side, the devices bring good communication range, and choosing the right frequency for your process can improve battery life as well as other factors. On the down side, the proprietary protocol blocks other wireless devices from your network. OT says you can connect a third-party device with an adapter, but it’s not the same as an open wireless network with different brands.

Last but not least, you have approvals and certifications to apply these devices in harsh and hazardous environments. On the datasheet, you can find all the certifications, compliance information, and extra device information.


OleumTech has an impressive wireless portfolio. The temperature solutions don’t offer much to thermocouple users, but overall the line has good advantages, especially if you have a long distance in a new application.

This video has more information about OleumTech’s temperature line:

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