Let's Talk Support: More Instrument Visibility With HART

Here is another way of doing remote instrumentation support. This method will use my laptop with a special software application on it called Field Care. My laptop is VPN'ed into the network here at the office. Pretend we're on the plant site, though. The network is going through the ethernet switch up there. The ethernet switch is connected to the—we'll call it the plant's control system, right here. 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 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 right here, 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 of a signal you're getting back from the radar and helps you really understand what's going on inside of the vessel that the device is trying to measure level within.

Okay, 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 not right is going on with the horn of the device. I could then direct the plant to check the horn of the device; clean it off. We will clean it off in this scenario, and then we will reload the echo curve.

All right, 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.