This article applies as of PRTG 24

Set specific scan times for PRTG sensors using the @ UTC hh:mm format in the PRTG web interface, with examples and notes on performance and time zones. 

How to set specific points in time as a scanning time for sensors

Sensors retrieve monitoring data in defined time spans called scanning intervals. PRTG comes with predefined scanning intervals that you can select in the sensor settings.

You can also set individual periods of time for sensor scans. For example, you can run a sensor every 30 seconds (30s), 15 minutes (15m), 12 hours (12h), and 24 hours (1d) by default. You can also define custom scanning intervals, like 20 minutes (20m) or 2 hours (2h). For more information, see PRTG Manual: Monitoring.

However, sometimes it can be convenient to run a sensor at certain points in time only. For example, you use an SQL sensor and want it to monitor your database only once a day at a given time, or you use an IMAP sensor to check your emails for successful backup messages that are delivered once a day at a particular time.

Follow these steps to define when you want a sensor to scan your network:

1. Go to Setup | System Administration | Monitoring in the PRTG web interface.
2. Go to Available Intervals. Here, you can enter the scanning intervals as well as the points in time at which you want your network to be checked. Use the following syntax and write each time definition in a new line.
   For one point in time: 

   @ UTC hh:mm

   For more points in time, write in one line: 

   @ UTC hh:mm , hh:mm
   @ UTC hh:mm , hh:mm , hh:mm
   @ UTC hh:mm , hh:mm , hh:mm , hh:mm

Notes:

• Define concrete points in time. It is not possible to use wildcards.
• PRTG supports up to 50 points in time.
• In the formula @ UTC hh:mm , hh:mm, you do not need to use a space before and/or after the comma. However, PRTG always saves the entries with a space both before and after the comma.

Examples:

• Enter @ UTC 08:00 when you want a sensor to scan every day at 8:00 A.M. For an everyday scan at 8:00 P.M., enter @ UTC 20:00.
• For more points in time at one go, enter @ UTC 09:05 , 09:25 if you want to scan at 09:05 A.M., and 09:25 A.M. every day. For three scans a day at 01:55 P.M., 02:00 P.M., and 02:05 P.M., enter @ UTC 13:55 , 14:00 , 14:05. For scans at midnight, 06:00 A.M., 12:00 A.M., and 06:00 P.M., enter @ UTC 00:00 , 06:00 , 12:00 , 18:00.

Note: Usually, sensor scans are executed at exactly the time you define here. If you encounter frequent divergences, your system might be overloaded. Keep in mind to set different points in time if you have many sensors that create a lot of workload together.

Note: The points in time for sensor scans are always based on the Coordinated Universal Time (UTC). Your local time may be different from the UTC: The PRTG web interface and reports use your local time.

Visualization

If you set @ UTC points in time to define a scanning interval for a sensor, the live graph always regards your data as 24h-interval data (corresponding to the every 24 h interval), although you might have defined more than one scanning time per day.

This means that in a default 120 values live graph, you will see a horizontal axis that covers a time span of 120 days, at least at the beginning of your measurements. With your historic data base growing bigger, the horizontal axis adapts if you set your sensor to scan more often than once a day.

More

• PRTG Manual: User Interface