PRTG - What is a Sensor?

Transcript - What is a sensor?

The concept of a sensor is really important within PRTG, so in this video, I'm going to explain exactly what we mean by a sensor.

When you're running PRTG, you will see that each device has a number of small, colored boxes that display information about that device. Each of these boxes is one sensor, and they are the basic monitoring elements in PRTG. One sensor monitors one single aspect on one device. For example, on a typical server, you would want to monitor the CPU usage, RAM, and disk space. Each of these things is one sensor. Since you usually want to monitor several things on each device, you will end up with multiple sensors per device. Let's look at a ping sensor now:
Here in the web interface we’re taking a look at the ping sensor. Inside a sensor you’re going to see we have channels. Channels are the metrics about a sensor, or which is really the data that we’re collecting. Different sensors have different amounts of channels depending on the sensors. Different device types allow for different amounts of data.

As you can see I want to go down now to my traffic sensor, that is going to have several more channels than the ping sensor. And you can see here we’re going to go through our traffic in/out/total and broadcasts. As you take a look at different sensor types you’re going to find that the data is going to vary.

PRTG offers over 200 pre-defined sensor types out of the box. We also have room for custom sensors, if there is a device type we don’t make a sensor for, that you need, many times you can get the MIB file from the manufacturer and make a custom sensor. On our website is a list of all our available sensor types. It’s a great way to go through and see what kind of sensors that we have for different device types, and also has the manual links to all the sensors and the prerequisites that you may need for the sensor types

Since the PRTG licensing is based upon the number of sensors you have, it's important to know how many sensors you are running in your environment. There are a few ways to find this out.

The first one is on the welcome page to PRTG. Here you can always see your total sensor count.

The second way is in your device tree along the top. You are going to always see, in parenthesis, this number is the total number of sensors you have. Keep in mind this number will include paused sensors. Paused sensors do not count in your sensor count.

The third way is on your system status of PRTG. If you go down into your database objects, you are going to also see your sensors count here.

We based our licensing on the number of sensors because we believe that is the fairest method. You pay for the sensors that you use. You have the freedom to put a lot of sensors on your critical devices and less sensors on your less important devices.

I hope you enjoyed this video and if you’re interested in more we have lots of other videos on our website. If you have any other questions, please contact us at support(at)

Thank you.