Let's Talk Support: More Instrument Visibility With HART

My name is Adam Dittbenner, and I'm the Instrumentation Manager for our Electrical & Instrumentation (E&I) services. This article and video have a high-level example of remote instrumentation support. This method will use my laptop with a special software application called Field Care. My laptop is VPN'ed into the network here at the office. For this scenario, we'll pretend we're on the plant site. The network is going through the Ethernet switch. The Ethernet switch is connected to—we'll call it — the plant's control system. And Allen Bradley Control Logix Ethernet rack. In this rack, this card here is a HART analog input card. It's not just a regular analog input card. It's got the HART enabled on it. So it's not just reading the milliamp signal from the instruments here on the table; it's also talking HART to them, as well.

My laptop is VPN'ed into this control rack, and I'm actually talking HART through this card to this instrument right now. So, on this instrument, it's upside down right now. We can take the display out to make it a little bit easier to look at. This instrument is currently reading 15.4% of its measured variable, and we can see that very same measured value on my laptop here.

I'm going to put an obstruction over the horn of this device. On a plant site, obviously, no one's going to put a metal cup over the horn of an instrument, but this could be a way of simulating an issue. Maybe sludge or gunk is covering the horn on one of your level measuring devices on a site. This is simulating that. Obviously, it throws off the reading quite drastically, and that reading is then also viewable on my laptop.

In order to troubleshoot something like that, you can't really get inside the tank, and you can't see that type of scenario. But if you're remotely dialed into the device, you can see that. You can go to the envelope curve of the device and pull a new echo reflection curve. This curve helps you diagnose how strong a signal you're getting back from the radar and helps you really understand what's going on inside the vessel that the device is trying to measure the level within.

I can pull up the echo curve. I can see that my echo curve is at a much higher threshold than it normally is. I could use that sort of data to help determine that something is wrong with the device's horn. I could then direct the plant to check the horn of the device and clean it off. We will clean it off in this scenario, then reload the echo curve.

We removed the metal cup from our level transmitter. Basically, the same effect of cleaning it in the scenario we're trying to set up here. And our readings have leveled out, our echo curve has returned to an acceptable value. And that's just one of the examples of how you can use remote instrumentation support through a VPN connection, through analog input HART-enabled cards, to get a little bit more data and graphical representation out of the instrument in order to troubleshoot.

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This article was updated on April 13, 2026.