PRTG Manual: SIMATIC S7-300/400 CPU Status Sensor

Enabled Beta Sensors experimental feature

This sensor requires that the Beta Sensors experimental feature is enabled.

For more information, see the Knowledge Base: What are beta sensors and how can I use them?

Credentials

This sensor requires connection settings for Siemens S7 in settings that are higher in the object hierarchy.

Parent device

This sensor requires that the parent device is a Siemens S7-300 or S7-400 programmable logic controller.

IPv4

This sensor only supports IPv4.

Performance impact

This sensor has a very low performance impact.

Lookups

This sensor uses lookups to determine the status values of one or more channels.

Limits

This sensor has predefined limits for one or several metrics.

Scanning interval

This sensor has a fixed minimum scanning interval for performance reasons. You cannot use a shorter scanning interval. Consequently, shorter scanning intervals in the Monitoring settings are not available for this sensor.

• The minimum scanning interval of this sensor is 1 minute.
• The recommended scanning interval of this sensor is 1 minute.

Maximum OB1 Cycle Time

Define a maximum cycle time for the program cycle organization block (OB1) in milliseconds. PRTG uses this value to calculate the value of the Cycle Ratio channel. Enter a positive integer.

You cannot change this value after sensor creation.

Primary Channel

Select a channel from the list to define it as the primary channel. In the device tree, PRTG displays the last value of the primary channel below the sensor's name. The available options depend on what channels are available for this sensor.

You can set a different primary channel later by clicking below a channel gauge on the sensor's Overview tab.

Graph Type

Define how this sensor shows different channels:

• Show channels independently (default): Show a graph for each channel.
• Stack channels on top of each other: Stack channels on top of each other to create a multi-channel graph. This generates a graph that visualizes the different components of your total traffic.
  You cannot use this option in combination with manual Vertical Axis Scaling (available in the channel settings).

Stack Unit

This setting is only visible if you select Stack channels on top of each other above.

Select a unit from the list. PRTG stacks all channels with this unit on top of each other. By default, you cannot exclude single channels from stacking if they use the selected unit. However, there is an advanced procedure to do so.

Result Handling

Define what PRTG does with the sensor result:

• Discard result (default): Do not store the sensor result.
• Store result: Store the sensor result and the last response in the \Logs\sensors subfolder of the PRTG data directory on the probe system. The file name is Result of Sensor [ID].log. This setting is for debugging purposes. PRTG overwrites this file with each scanning interval.

This option is not available when the sensor runs on the hosted probe of a PRTG Hosted Monitor instance.

In a cluster, PRTG stores the result in the PRTG data directory of the master node.

CPU Status

The CPU status of the PLC

• Up status: RUN (solo mode), RUN-R (redundant mode)
• Down status: DEFECTIVE, NO POWER
• Warning status: HOLD, LINK-UP, SELFTEST, STARTUP (cold restart), STARTUP (hot restart), STARTUP (warm restart), STOP (update), STOP (reset memory), STOP (self-initialization), STOP (internal), UPDATE
• Unknown status: Unknown

This channel is the primary channel by default.

Cycle Ratio

This channel is only visible if you define a maximum OB1 cycle time during sensor creation.

The cycle ratio of the PLC. PRTG divides the most recent OB1 cycle time by the maximum cycle time you define in the Maximum OB1 Cycle Time to calculate this value.

This channel has default limits:

• Lower error limit: 70%
• Lower warning limit: 80%
• Upper error limit: 100%

Cycle Time Events

If the Cycle Time Exceeded (W#16#3501) event occurred

• Up status: OK
• Down status: Cycle Time Exceeded
• Warning status: Diagnostic Buffer Overflow
  Diagnostic Buffer Overflow happens when the number of events surpasses the diagnostic buffer limit between sensor scans, which prevents PRTG from finding the last known event. The events PRTG cannot detect might include a Cycle Time Exceeded event.
• Unknown status: Unknown

Downtime

In the channel table on the Overview tab, this channel never shows any values. PRTG uses this channel in graphs and reports to show the amount of time in which the sensor was in the Down status.

OB1 Cycle Time

The most recent OB1 cycle time

OB1 Max. Cycle Time

The maximum OB1 cycle time since the last restart of the PLC

OB1 Min. Cycle Time

The minimum OB1 cycle time since the last restart of the PLC