Comparison: GE DPI 620 Genii vs AMS Trex Communicator

Comparison time again! Everybody digs these. I know you end users like to stay updated on cool device features, and you vendors want to check out your competitors. Don’t front, I see you out there. 😉

We already chatted about the usefulness of tools with feature combos. When you have to hit the field, you want a device that can provide communication, diagnostics, electrical measurements, and more. We all want to spend our precious time doing other things, right?

Well, today we have a heavyweight bout for you, two big companies with outstanding tools! On the left, the experts from Emerson, back again with the AMS Trex Communicator. No doubt about their expertise with handheld and instrumentation in general, right? On the right, we have the crew from GE bringing the DPI 620 Genii. We haven’t seen much of them here as yet, but they also have a lot of experience with instrumentation and automation in general.

Let’s dive into the features universe and find out how these devices can support your daily activities. You ready?

Then grab some popcorn, 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.


The DPI 620 Genii has a fancy design, with the display as one of its highlights, and simple connections, which make your job easier. Great one-two punch straight out the gate! It doesn’t have a local keypad, but I consider this a plus. I’ve said before that nobody uses the keypad, so why bother with it? The onscreen keyboard works just fine.

Courtesy of GE and Emerson Automation Solutions

I really like the menu design too, and how you can swipe and gesture to navigate. Vendors need to think in this sort of detail or get left behind by their competitors, and the DPI 620 offers a positive user experience.

On the other side, the AMS Trex has a simple design but a big display at 14.5 centimeters! That gives you enough room to navigate the menus using one or both hands. Nice. It’s heavier than the DPI 620, weighing 1.33 kilograms against 0.57. It’s also bigger, at 201 x 141 x 61.1 millimeters versus 183 x 114 x 42. However, the Trex scores a good blow with that display size, 14.5 versus 11!

Protocol support

Let’s talk about setting up a field device, whether in the field or the workshop. The DPI 620 has more supported protocols, giving you more flexibility. It comes standard with HART, but you can add Foundation Fieldbus (FF) and PROFIBUS PA. All of them have libraries with device description (DD) files, and you can update for free! Yes! If you have a non-registered DD, you can contact GE to help you install it.

The AMS Trex will let you connect with HART and FF devices, but no PROFIBUS PA here. On the other hand, Emerson has a huge library for HART and FF devices, so it’ll probably cover most of your needs, and you can update it if you need more. By the way, now you don’t need to buy the upgrade license to update the library! I don’t know whether to say “Well done!” or “Finally!” here, but it does make me happier.

Loop power

We all want devices that can function without having to schlep a bunch of items for power and whatnot. The DPI 620 is totally chill in this area; you can power up all HART, FF, and PROFIBUS PA devices with it. And for HART devices, you don’t need an external resistor, because the internal resistor will do it with no problem. If you don’t need to power up the device, then you can connect the DPI 620 to the segment or directly to the device communication port. For FF and PROFIBUS, you can use the internal terminator to create a network for supplying power. You can also just connect to the network without power or terminator.


Courtesy of GE and Emerson Automation Solutions

The AMS Trex comes in two versions. One can only communicate with HART and FF devices. The other can provide power for the devices and read current as well. With version two, powering up HART devices is a snap, but FF devices need an external connection, which is kind of disappointing, as most competitors can do that with their software. Also, I really would like to see PROFIBUS PA here. Wish I knew why Emerson avoids this protocol.

Fancy features

You can do a ton of things with the DPI 620, like watch a movie on it. Just kidding! Still, it has a lot of great features. Frankly, its ability to read and generate signals is on par with its communication with field devices. You can use up to 6 channels simultaneously to source and measure signals such as current, volts, ohms, and frequency. Furthermore, you can read and simulate thermocouples and RTDs.

Ooh, ooh, and the analysis and data logger! When you need to compare a reference source with a field device, you can set up a channel as your reference and connect the device to another channel. Then you can compare the difference between the channels. The data logger lets you record process values to analyze afterward, and the device has 4 GB internal flash memory and an 8 GB removable microSD card! Not bad at all, right?

The AMS Trex keeps it pretty simple. Here we can highlight the different ways to connect the AMS Trex to your computer or AMS Suite, like with the wifi connection, where you can update more than one Trex using the wifi automatically. It comes with Bluetooth and USB connections as well, which I like.

Courtesy of Emerson Automation Solutions

If you have the valve positioner from Emerson, the AMS Trex has a ValveLink app already installed to diagnose your valves using the positioner. And the Emerson reps hint at more features in the near future, so we’ll see.

Calibration and diagnostics

The DPI 620 began life as a modular calibrator before the developers started attaching features to it. That means you can use modules to generate and measure pressure or temperature or whatever for your field device. I like this option because you can just add the module and calibrate, then remove it! You can also transfer data with GE’s calibration software. Then we have the Run Procedure feature, where you can create a routine to calibrate a field device or download routines from the software.

Courtesy of GE

Although the AMS Trex can’t calibrate, it does offer field network analyses where the DPI 620 doesn’t, like for diagnosing your FF goodies. If you have the FF network in your plant, it will allow you to verify problems with devices or the network. Plus you have the option to measure the current output, which means you don’t need to drag a multimeter with you!


One of these tools can help you set up in HART, FF, and PROFIBUS PA, generate electrical signals, and calibrate your devices. The other provides HART and FF field communication, current readings, and FF network diagnostics. Which will work best for you? You tell me. Which of these features do you need the most?

Table of comparison

Table of Comparison AMS Trex DPI 620
Courtesy of GE and Emerson Automation Solutions



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