Comparison: Liquiline M CM42 vs KNICK Stratos Pro

Does the analytical stuff baffle you? Yeah, me too. Some companies have a separate team taking care of the analytical system in the plant, some have the same team in charge of both universes, and things work fine either way.

In my career, I mostly worked with vendors who went with separate teams, and each team had its own experts. Even if the service team worked with different principles, you always had experts with entirely distinct concepts, skills, and such for the analytical devices.

We here at Visaya strive to simplify, offering clear and easy explanations about various topics. For June, we’re focusing on pH measurement and analytical transmitters. Today, we have our second analytical transmitter comparison, and we brought two big players in this market!

On the left, the gang from Endress+Hauser have returned to the Visaya ring with the Liquiline M CM42. On the right, we welcome the crew from KNICK to their first comparison on Visaya, and the Stratos Pro will represent the brand in this battle. Let’s dive into the features and find out how these devices can support you in a new application.

Grab a frappuccino, take a seat, have a read, and draw your conclusions!

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


On the Endress side, no big surprises here! The Liquiline M CM42 looks like most transmitters on the market, and this is okay. Users feel comfortable with this familiar design. It has a good-sized display, and the local keypad has a softkey that lets you scroll through the options, making navigation through the configuration tree easier. The design only has a few details, but the local setup and the display size make up for that.

Unboxing Liquiline M CM42 vs Stratos Pro
Courtesy of Endress+Hauser and Knick

On the KNICK side, the Stratos Pro design has a smaller display but a good backlight and local setup. The local setup has arrows and buttons on the faceplate to go through the menu tree. It also has a setup guide, so you won’t need the manual next to you during installation.


The Liquiline M CM42 can measure pH/oxidation-reduction potential (ORP), conductivity, or oxygen. However, it only has a single channel, so you need to pick your application then implement the device. Beyond that, you can use analog or digital sensors. If you’ve never used a digital sensor before, then you can try it out with this device.

The Stratos Pro measures the same process variables, but here you have more channel flexibility, with two digital inputs, one analog input, and two current outputs! Not bad at all. It too can support digital or analog sensors. Both vendors support Memosens technology, so you’re not tethered to one supplier if you need a new sensor for either of these devices.

Housings and approvals

Also, both vendors designed these devices to apply to multiple industry segments, so they should cover a wide range of requirements, right?

You can use the Liquiline M CM42 in industries such as food and beverages, chemical, and life sciences. If your process requires approvals for hazardous areas, it has explosion protection approvals like ATEX, IECEx, etc. It comes in a plastic housing for most applications or stainless steel for hygienic processes. The plastic housing brings the dimensions around 144 x 144 x 159 millimeters with a weight of 1.5 kilograms, and the steel sits at 174 x 174 x 145 millimeters and 2.1 kilograms.

Housing Liquiline M CM42 vs Stratos Pro
Courtesy of Endress+Hauser and Knick

The Stratos Pro also has approvals allowing the application in hazardous areas up to Zone 1. The plastic housing is 148 x 148 x 117, keeping the weight around 1.2 kilograms. Although it lacks other enclosure materials, you can contact a rep and ask for more options.

Power and protocols

Both devices are loop-powered, meaning you can have the signal and the communication in the same cables. With a new installation, these devices can save money on installation over four-wire devices. Of course, you know I’ll wave the wireless flag here, because it would make a good option, but we’ll get there. Eventually.

The Liquiline M CM42 has only a few protocols to send data to your control system, analog, HART, FOUNDATION Fieldbus (FF), and PROFIBUS PA (PB). But the Stratos Pro floats in the same bucket, so it’s a tie here. You can find most of the files you need for these devices on each vendor’s website, and we’ll talk about the sites in a moment.

Fancy features

The Endress+Hauser device doesn’t have much in the way of fancy features, but if you want the fancy stuff, then you should check out the other transmitters in the company’s portfolio. I will say that the versatile graphic display with the onscreen sensor monitor almost counts as fancy here.  And the modular design makes maintenance in the field easier, which is always yay.

Stratos Pro Color Displays
Courtesy of Knick

The KNICK device delivers a cool feature with its display, six colors to indicate the status of the device. That means you can see from a good distance if your devices are working properly or if you have a problem. You can use it to light up the field for Christmas, too! Just kidding.

Information and documentation

I’ve talked a lot about the Endress+Hauser website, but it hasn’t improved yet! Actually, it’s really difficult to find devices on the site, and don’t even bother trying to use your phone to do it. And the technical information says you can learn more from the operating instructions. Guess what I couldn’t find for the Liquiline M CM42? Yeah, somebody stuck it under a different name. Not impressed.

Websites Liquiline M CM42 vs Stratos Pro
Courtesy of Endress+Hauser and Knick

On the KNICK site, you run into similar problems with the lack of responsiveness and the difficulty in finding information. The documentation is easier to find but more poorly edited than on Endress+Hauser’s site. You’ll need a snack and a good chunk of time for either site.

Table of comparison

Table of Comparison Liquiline M CM42 vc Stratos Pro
Courtesy of Endress+Hauser and Knick


You can use either device in a variety of similar applications, so you have two good players on the market here. Scale them out, price them, and pick the one with the most features relevant to your application.

Buy the Liquiline M CM42 in our online shop


Find and buy the right oxygen analytical transmitter for your application

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