In the channel settings of some sensors I have the option to choose a value mode. What are the differences between these three modes?
This article applies to PRTG Network Monitor 13.2.5 or later
Value Mode in Channel Settings
PRTG offers a special channel setting for sensor channels which show absolute values (so this setting is not available for traffic channels, for example). The section Value Mode in these channel settings provides three options to display values in historic graphs and tables:
- Average: Shows average values in historic graphs and tables. The average is calculated over all measurements in a specific table/graph time span.
- Minimum: Shows minimum values in historic graphs and tables. The minimum is the lowest monitored value in a specific table/graph time span.
- Maximum: Shows maximum values in historic graphs and tables. The maximum is the highest monitored value in a specific table/graph time span.
Single table and graph time spans depend on the chosen historic data interval. The default historic tables and graphs are:
- Live Data: Shows values of each scanning interval as defined in the sensor settings.
- 2 Days: Values are shown in 5 minute intervals.
- 30 Days: Values are shown in 1 hour intervals.
- 365 Days: Values are shown in 1 day intervals.
The following table illustrates which value will be displayed in the graph at each calculation point or in the first line of a sensor's historic data table for each option:
|Average Mode||Minimum Mode||Maximum Mode|
|Live Data||value of last sensor scan||value of last sensor scan||value of last sensor scan|
|2 Days||average of all monitored values in the last 5 minutes span||lowest value of all monitored values in the last 5 minutes span||highest value of all monitored values in the last 5 minutes span|
|30 Days||average of all monitored values in the last 1 hour span||lowest value of all monitored values in the last 1 hour span||highest value of all monitored values in the last 1 hour span|
|365 Days||average of all monitored values on the last day||lowest value of all monitored values on the last day||highest value of all monitored values on the last day|
Note: If the scanning interval is longer than the time span in one of the historic data graphs, the values will be displayed as dots in this graph. For example, if a sensor has a scanning interval of 60 minutes, the 2 days graph will only show dots because it is calculated in 5 minute intervals.
Value Modes and Gauges
Gauges on device and sensor overview tabs show an average symbol x̄. This average also depends on the value mode. The average is based on the values as shown on the “30 Days” tab. So if you choose the minimum or maximum mode, then the average is calculated over the minimum or maximum values as given on the “30 Days” tab, i.e., based on the minimums or maximums of every 1 hour time span on the last 30 days.
For example, consider an HTTP sensor which shows the loading times of a webpage. It might have a scanning interval of 1 minute, so usually there would be five sensor scans within a 5 minutes interval.
Let’s assume the following latest five sensor scan values as listed in the data table on the “Live Data” tab:
|Date Time||Loading Time|
|24.04.2014 13:44:39||9 msec|
|24.04.2014 13:43:39||6 msec|
|24.04.2014 13:42:39||3 msec|
|24.04.2014 13:41:39||6 msec|
|24.04.2014 13:40:39||1 msec|
Then, on the “2 Days” tab which shows values for 5 minutes time spans, the three value mode options would result in the following data for this interval:
|Date Time||Loading Time (Value Mode Average)||Loading Time (Value Mode Minimum)||Loading Time (Value Mode Maximum)|
|24.04.2014 13:40:00 – 13:45:00||5 msec|
(lowest measured value)
(highest measured value)
The values for the other historic data tabs will be calculated and shown accordingly (e.g., average over the measured values within 1 hour on the “30 Days” tab). Note that there might be rounding differences when calculating averages.
Graph for Different Value Modes
Consider the following values. They were monitored with a 60 seconds scanning interval of the sensor which means that there are 5 scans in 5 minutes. For the 2 days graph and table, after each 5 minutes time span one value is calculated depending on the value mode (avg, min, and max):
|Scan 1||Scan 2||Scan 3||Scan 4||Scan 5||Avg Mode||Min Mode||Max Mode|
|13:40:00 - 13:45:00||9||6||3||6||1||5||1||9|
|13:45:00 - 13:50:00||2||3||2||2||2||2,2||2||3|
|13:50:00 - 13:55:00||2||3||2||4||1||2,4||1||4|
|13:55:00 - 14:00:00||1||5||4||4||6||4||1||6|
|14:00:00 - 14:05:00||2||6||3||2||2||3||2||6|
The following graph illustrates the differences between the value modes (Avg, Min, Max) in a 2 days graph (actually, this graph would be a snippet from the whole 2 days graph in each mode):
I get value as bytes from my custom library sensor , How can I convert and display it as Mega Bytes in graphs ? Can this channel value help me in doing this ?
You can change that in the device settings under "Channel Unit Configuration". This goes for all sensors that the device has.
How can I disable the limits for one sensor with multiple channels at once?
I´m afraid, that is not possible. We will put your feature request onto our wishlist stack!