Buyer guide: Rosemount 848T and SMAR TT481WH
Hey, gang! Y’all ready for a riveting encounter with temperature transmitters? I thought so. Let’s eyeball a couple of top devices, the 848T from Emerson’s Rosemount line and the TT481WH from SMAR.
Emerson has produced a clutch of versatile little devices that usually sit at the top of the automation market. Let’s see if the Rosemount 848T lives up to that legacy.
If you’ve been in automation a while, then you know that Emerson has had the 848 floating around for several years. But did you know that it still holds up against its latest competitors in the market? Well, it does, at least in data capture and built-in wireless.
Speaking of wireless, the 848T takes up to four sensors with no tangle of cable running from the field to the control room. The data can join its buddies in your system through protocols like Modbus, EtherNet-IP, and OPC, which is nice.
Words like robust and flexible best define the 848T. You can measure variables across the plant with ease. Of course, any device with pros always comes with cons. It won’t supply energy to your field device and has a standard accuracy of 0.3 degrees Celsius with two years of stability. Meh. Lastly, it only does remote monitoring. If you want a local display and remote monitoring, then check out Visaya’s device page.
On the plus side, if you have a third-party gateway on wirelessHART, the 848T will connect with no problem. It also has a simple setup that only needs a plant access management system or handheld with the correct device description file (DD) to get full access. Pretty neat, ain’t it?
If you go far enough out, you’ll need a repeater to boost your signal, and they ain’t cheap. But wait! The 848T has an extended range option, which may let you skip the repeater! And its battery can give you up to 10 years without fuss. Ideally, of course. Playing around with Emerson’s power module life estimator, we found that at 16 seconds of update rate in a strong network, the module could last 2.4 years.
In general, the 848T comes equipped with great versatility and a little fanciness, always a nice combo in the automation industry.
You smart about SMAR? This little clan offers an impressive range of wireless solutions. So let’s welcome the TT481WH and see what we can reveal!
The SMAR TT481WH looks like a junction box, no lie. But it lets you connect RTDs and thermocouples and other stuff, and it’ll send all your data wirelessly. But you have to pick your input before you buy the device, which smells like a minus to me. On the other hand, it installs easily, so yay for that.
Boo on the lack of deets for certs, though. For hazardous areas, the docs say “pending.” Seriously? Step up, SMAR.
The TT481WH can measure temps through any of its four (or eight) inputs. And when you want to swap out your old mechanicals, the TT481WH makes a nice upgrade. The multiple inputs save you dough on installation too. Sucks that it has a poor signal range, though. The money you save on installation you may spend on repeaters unless you keep it close.
Still, it offers good accuracy, around 0.03 percent, and you can set it up with a handheld or a laptop on various platforms.
The TT481WH can save you cash both on its own purchase and its ability to monitor several parameters in the same area. Its familiar design – just like most other wireless devices out there – will save you time and hassle in setup. You can do it through your handheld, as long as you have the right files for whatever platform you use.
You might run out of battery juice, though. The website claims up to seven years, but the manual says four. Who’s right? Who knows? Does anybody out there have an answer? If so, please drop us a line.
Bottom line – if you want fast, cheap installation, then it couldn’t hurt to start with SMAR.
Table of comparison
|sharp, precise design, but no local configuration||simple design, internal display|
|50-100 meters, expandable to 250||lacks extended-range antennas, requires repeater|
|four inputs that can support RTDs, thermocouples, volts, ohms, and analog; needs adapter for volts||four or eight inputs for RTDs, thermocouples, volts, ohms, and analog; have to pick before buying|
|+-0.3 degree Celsius, depending on the sensor||0.03 percent|
General information and documentation
|smartphone-friendly site, can find files easily; online manual and helpful videos||sloppy, hard-to-find documentation|
So either of these devices could make your process monitoring easier. The Rosemount 848T looks fancier than the SMAR TT481WH, but if you need to watch the wallet, then go for the SMAR device. Or check out others that we have floating around here. Happy shopping!