<%NUMBERING1%>.<%NUMBERING2%>.<%NUMBERING3%> PRTG Manual: Sensor Channel Settings

Name

Enter a meaningful name to identify the channel (not editable for script sensors after sensor creation). The name will appear in graphs and tables.

You can automatically add the sensor's ID to the name by using the placeholder [#id].

Unit

This field is only visible for custom sensors.

Enter the unit for the values that this sensor returns. Enter a string. This unit string is used for display purposes and will be shown in graphs, data tables, and gauges.

If you want to change the Unit after having created the sensor, you can change it in the sensor's channel settings.

Scaling Multiplication

This field is only visible for channels with a custom unit. If you want to multiply the received raw data by a certain value, enter the multiplier here. Otherwise, use the default value 1 to not change the received value. Enter an integer value.

For example, the following sensors provide the scaling factor for received values with custom units in their settings.

• Sensor Factory Sensor (you can use multiplication and division in the channel definition)
• SNMP APC Hardware Sensor
• SNMP Custom Sensor
• SNMP Dell Hardware Sensor
• WMI Custom Sensor

If the sensor channel uses lookups, the scaling factor will not modify the values that are defined by the lookups. Any applied lookup always uses the raw value as retrieved from the target device. If you use a scaling factor for such a channel, you will notice the scaling in data graphs, but the channel value will appear unmodified in data tables.

Scaling Division

This field is only visible for channels with a custom unit. If you want to divide the received raw data by a certain value, enter the divisor here. Otherwise, use the default value 1 to not change the received value. Enter an integer value.

For example, the following sensors provide the scaling factor for received values with custom units in their settings.

• Sensor Factory Sensor (you can use multiplication and division in the channel definition)
• SNMP APC Hardware Sensor
• SNMP Custom Sensor
• SNMP Dell Hardware Sensor
• WMI Custom Sensor

If the sensor channel uses lookups, the scaling factor will not modify the values that are defined by the lookups. Any applied lookup always uses the raw value as retrieved from the target device. If you use a scaling factor for such a channel, you will notice the scaling in data graphs, but the channel value will appear unmodified in data tables.

ID

Shows the ID of the channel. You cannot change the ID. PRTG uses it for unique identification. For example, you need the ID when using Sensor Factory sensors.

There are a few special, fixed channel IDs.

• -1 is for sum channels of traffic sensors (for example, of the SNMP Traffic sensor).
• -4 is for the Downtime channel (you can use it, for example, for an uptime percentage calculation in a Sensor Factory sensor).
• -2 (coverage) and -3 (error) are internally used.

Limits

This setting is not available for custom channels.

Define if you want to use thresholds for this channel. The channel can affect the status of the sensor it is part of. With limits you can define when the sensor will show a Warning or Down status, depending on the channel data. For example, you can use this function to set a traffic sensor (which is usually never in a Down status) to error when the monitored values reach critical limits.

Choose between:

• Disable limits: Do not use the channel data to control the sensor status.
• Enable alerting based on limits: Define limits for numerical values returned by the device. Additional fields appear below. The sensor of this channel will enter a Warning or Down status when limits are undercut or overrun.

The limits option is not available for the Downtime channel.

You can show limits in graphs (highlighted in yellow or red) if you select exactly one channel with a limit in a graph.

Value Lookups and Limits

This setting is only available for custom channels.

Define when the channel will show a down status and alert you, either based on the lookup definition or based on thresholds for returned values. Only the option that you choose will apply. For example, if you choose limits as alerting method, an error status defined in the lookups will not show up.

Choose between:

• Enable alerting based on lookups: Use the lookup definition of the channel to control the sensor status. Make sure the channel uses a proper Value Lookup if you choose this option. Select the lookup file either in the channel settings below or in the sensor settings, depending on the sensor. If you do not want to use the channel data to control the sensor status, select None as Value Lookup.
• Enable alerting based on limits: Define limits for numerical values returned by the device. Additional fields appear below. The sensor of this channel will enter a Warning or Down status when limits are undercut or overrun.

If you choose limit-based alerting, errors and warnings that you have defined in the lookup file will not apply!

Value Lookup

This field is only visible for custom sensors and if you select lookups-based alerting. Select the lookup file that you want to use with this channel.

Do not use this option for sensors that provide the unit Value Lookup in the sensor settings. The channel setting will be overwritten with the next sensor scan. Define the lookup file that you want to use with this channel on the Settings tab of the sensor. Choose the option Value Lookup for the setting Sensor Channel #x Unit (where x is the number of the channel) and choose the desired lookup file under Sensor Channel #x Value Lookup. See section Define Lookups—Requirement: Channel Unit "Custom" for affected sensors.

If you choose None, alerting by lookups and limits will be disabled and channels will not appear as lookup. If you want to keep the lookup representation without alerting, define the states accordingly in the lookup file.

Upper Error Limit ([unit])

This field is only visible if you enable Enable alerting based on limits above. Specify an upper limit for a Down status. If the channel values overrun this value, the sensor will be Down. Enter a valid number into at least one of the limit fields.

While a sensor shows a Down status triggered by a limit, it will still receive data in its channels.

Upper Warning Limit ([unit])

This field is only visible if you enable Enable alerting based on limits above. Specify an upper limit for a Warning status. If the channel values overrun this value, the sensor will be Warning. Enter a valid number into at least one of the limit fields.

Lower Warning Limit ([unit])

This field is only visible if you enable Enable alerting based on limits above. Specify a lower limit for a Warning status. If the channel values undercut this value, the sensor will be Warning. Enter a valid number into at least one of the limit fields.

Lower Error Limit ([unit])

This field is only visible if you enable Enable alerting based on limits above. Specify a lower limit for a Down status. If the channel values undercut this value, the sensor will be Down. Enter a valid number into at least one of the limit fields.

While a sensor shows a Down status triggered by a limit, it will still receive data in its channels.

Error Limit Message

This field is only visible if you enable Enable alerting based on limits above. Enter an additional message. It will be added to the sensor message when showing a Down status. Enter a string or leave the field empty.

Warning Limit Message

This field is only visible if you enable Enable alerting based on limits above. Enter an additional message. It will be added to the sensor message when showing a Warning status. Enter a string or leave the field empty.

Graph Rendering

Define if you want to show this channel in data graphs. Choose between:

• Show in graphs: Sensor graphs contain the data of this channel.
• Hide from graphs: Sensor graphs do not contain data of this channel.

If you choose to hide this channel in graphs, it will also not appear in the graph of a Report.

Table Rendering

Define if you want to show this channel in data tables. Choose between:

• Show in tables: Sensor data tables contain the data of this channel.
• Hide from tables: Sensor data tables do not contain the data of this channel. This option hides the channel gauge as well, but the channel will still be available in the data table of the sensor's Overview tab.

If you choose to hide this channel in data tables, PRTG will also not use it for the calculation of the "sum" (total) channel of a sensor. It also will not appear in data tables of a Report.

Line Color

Define the color of the channel display in graphs. Choose between:

• Automatic: PRTG automatically sets the color of this channel in graphs.
• Manual: Individually define the color of this channel. You can enter the desired color code below.

Color (#rrggbb)

This field is only visible if you enable Manual above. Enter a color in hexadecimal RGB notation as in .html and .css files, or choose a color from the visual color selector. The field with the hexadecimal color value will change to the selected color automatically.

Line Width

Define the width of the channel line in graphs. Enter an integer value in pixels. The maximum line width is 25 px, but we recommend that you only use values between 1 and 7 to get optimal results.

Data

This setting is available for most channels. Define how to display data. Choose between:

• Display actual values in [unit]: Display the values in the shown unit.
• Display in percent of maximum: Calculate and show percent values based on a maximum value. Provide a maximum below.
  If you choose this option, you cannot display the data of traffic sensors as a positive and negative area graph.
   
  If you choose this option, existing values in the Limits section will be counted as percent values.

Maximum ([unit])

This field is only visible if you enable Display in percent of maximum above. Enter a value to use as maximum. Consider the given unit. PRTG will calculate all percent values based on this value.Enter an integer value.

Value Mode

This setting is only available for sensor channels that return absolute values. It is not available for sensors showing difference values, such as traffic channels. Depending on this setting, the channel can not only show averages, but also minimum or maximum values in the graphs for the respective time spans.

Choose from:

• Average: The channel shows average values.
• Minimum: The channel shows minimum values.
• Maximum: The channel shows maximum values.

For more information about value modes, see the Knowledge Base : What is the Value Mode in channel settings?

Decimal Places

Define how many decimal places of the channel's data to display in graphs and tables. Choose from:

• Automatic: PRTG automatically defines how many decimal places are used for optimal viewing results.
  Values between 10 and –10 are rounded to two decimal places. Values that are very close to an integer are rounded to the integer, for example, 3.001 is rounded to 3.
• All: Display all available decimal places.
• Custom: Manually define the number of decimal places. If you choose this option, an additional field will appear. Enter an integer value.

Spike Filter

You can use a spike filter to correct faulty monitoring data. Sometimes, sensors report values that are enormously high or far too low. This can be because of an error in data transmission, or because of incompatibilities of the physical device you are monitoring. This can make graphs unreadable. A spike filter can compensate for these flaws.

If you enable a spike filter, values above and below a certain limit are disregarded in the monitoring data for graphs and tables.

Choose between:

• Disable filtering: Display all data as it is received. Do not filter out spikes.
• Enable filtering: Enable a filter to remove spike values. Additional fields appear below.
  This does not change monitoring data itself but only the presentation of the data. This setting is valid for all data of this channel, including historic data.

Use the spike filter with care. For overflow values in SNMP sensors, check the SNMP Compatibility Options before.

The spike filter option is not available for the channel Downtime.

Spike Filter Max. Value ([unit])

This field is only visible if you select Enable filtering above. Enter the maximum value to show in the channel data. PRTG will disregard all data above this value in graphs and tables. Enter an integer value or leave the field empty.

Spike Filter Min. Value ([unit])

This field is only visible if you select Enable filtering above. Enter the minimum value to show in the channel data. PRTG will disregard all data below this value in graphs and tables. Enter an integer value or leave the field empty.

Vertical Axis Scaling

Define how to display the vertical axis for the channel in graphs. Choose between:

• Automatic scaling: PRTG automatically uses the optimum scaling. Usually the scaling ranges from the minimum to the maximum value. PRTG uses one single scale for each unit label only.
• Manual scaling: Define the scaling manually. Additional fields appear below. Defining manual axis scaling can make low values better visible in your graph, but it may result in a graph with multiple vertical axes for the same unit label.

Settings for this option are ignored if you enable the Graph Type Stack channels on top of each other or Show in and out traffic as positive and negative area graph (available for traffic sensors) on the sensor's Settings tab.

Vertical Axis Maximum ([unit])

This field is only visible if you enable Manual scaling above. Enter the maximum value to use on the vertical axis for the channel. Enter an integer value.

Vertical Axis Minimum ([unit])

This field is only visible if you enable Manual scaling above. Enter the minimum value to use on the vertical axis for the channel. Enter an integer value.