Buyer guide: Rosemount 648 and ABB TSP300-W

Hey all! Good to be back! Today, we’ll check out two solid temperature devices that have rocked the market for a while now – the Rosemount 648 and the ABB TSP300-W.

But before we look at these product reviews, we need to remind you that they examine only the features of each product, not their performance. You’ll have to discuss the devices in the comments with people who’ve used them to find out how they do on site.

So, chop-chop – let the feast begin!

Gif for let ithe feast begin
Courtesy of giphy

Rosemount 648

Yep, more Emerson. Because you know how it works around here. We plan to review as many as we can, and Emerson has a bunch.

So let’s have at the Rosemount 648 temperature transmitter, with its X-well sensor. Emerson wants to redefine surface sensors, and I like the attitude! Surface sensors fall short in the accuracy department, for sure. But Emerson claims that the 648 solves this issue. We’ll see about that.


A Rosemount by any other name will look just the same. Take that, Shakespeare. So yeah, Rosemounts have a look. But it comes with wireless built in and can take an assortment of sensors such as thermocouples and bimetallic strips.

image of Rosemount 648
Courtesy of Emerson

The wireless option makes it a snap to check. Of course, if you don’t have wireless, get thee to a gateway! Besides that, the 648 offers good system protocols for easy integration. And we all know temp is slow, so the update time will cover you, no prob.


Says here the batter has an ideal life of over 10 years – emphasis on “ideal,” natch. But Emerson thought of that! Emerson’s a power module lifcalculator can spit out the actual life of your battery when you dump your process numbers in.

So say you want the sensor to have a one-second update time at 30 degrees Celsius. Ding goes the calculator – and your battery will last less than a year. That sucks. So how about a 16-second update? Ding – seven years! We’ll have some of that, please.


Now let’s chat about the X-well sensor. The 648 takes Emerson’s 0085 pipe clamp sensor (aka the X-well) and yields good results, one of them being the elimination of a thermowell. The 648 combines the surface and ambient temps with the pipe info to find the process temp. And that means no need for a thermowell. Best of all, Emerson plans to include this feature in all their temp devices. Thanks, Emerson!

Installing an X-well sensor is cheap and quick, but like always, you have a drawback somewhere This device doesn’t work as well in fast control loops, safety monitoring, and fiscal metering. So hope you don’t have one of those!

Emerson claims the 648 provides an accuracy of 0.0025 degrees Celsius, depending on the environment, of course. And you can tack on an extended antenna to improve signal quality and range, which means you don’t have to shell out for a repeater. Yay on that.

ABB SensyTemp TSP300-W

Yep, ABB again too. I really dug that Coriolis meter, so I wanted to scope another ABB product. Anyway, time for the TSP300-W! ABB claims to have bumped battery life on this one. Wanna know how? Then keep reading!


The TSP300-W has wireless HART built in – lovely, that. We’ve discussed the benefits of wireless, so we’ll skip that today. It also comes with installation options which can support a hodgepodge of processes. You can set it up with a thermowell, if you like strong accuracy and performance. But if you prefer easy, then go with a surface sensor.

image of ABB TSP300-W
Courtesy of ABB

You can also match the TSP-300W with various sensors and a local display for setup and visualization. But you need a certain distance between the electronics and the pipe to avoid temp issues. It has certifications for zone 0, zone 1, or zone 2 hazardous areas, too. The manual has the deets on that.


A surface sensor can measure from -40 to 150 degrees Celsius, and the transmitter can hold up from -40 to 70 degrees Celsius. If you opt for the thermowell, then the range will depend on the sensor you choose.

One really awesome aspect worth mentioning is the TSP300-W’s built-in energy harvester, which increases the battery life. Thermoelectric generators for the win! They recharge batteries through temperature differences between the process and the environment. So cool!


Surface sensors provide a lot of pluses in installation, maintenance, and replacement. And as they improve in accuracy and performance, they’ll become common, maybe even the default. They can provide update times from four seconds to nearly an hour, giving you all kinds of options for your control system.

image of ABB TSP300-W
Courtesy of ABB


Table of comparison




Rosemount 648





similar design to other Rosemount devices; wireless and display come standard
similar design to other ABB devices; display comes standard




 LCD display rotates, but no local setup without a handheld LCD display and can set up without a handheld




thermocouples, RTDs, ohms, and millivolts; can take surface sensors thermocouples, RTDs, ohms, and millivolts; can take surface sensors or two sensors



Surface monitoring

0085 pipe clamp sensor can work in any application other than fast control loops; good accuracy
-196 to 600 degrees Celsius; energy harvester requires different min/max calibration




standard external antenna; extension optional; update time from 1 sec to 1 hr only one option for wireless,which covers up to 300 meters; update time from 4 sec to 1 hr, but 16 sec advised



Battery life

ideally 10 years; power module life estimator can predict actual life with process info ideally 7 years, but has energy harvester



So both of these devices can put it down. But do you want to pick one up? Well, scale out and decide. Or poke around our device page to see what else Emerson and ABB have up their sleeves. Happy hunting!


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