This article applies to PRTG Network Monitor 18 or later

Workaround for ''x' is not a valid floating point value'

You might receive the error message 'x' is not a valid floating point value when you use SNMP Custom, SNMP Custom Advanced, or SNMP Library sensors to monitor an OID that returns a value with a comma "," like 27,5545 as a float value.

Check the Value Returned by the OID

• Download and install SNMP Tester.
• Open the SNMP Tester and enter the following information.
  • The Device IP/Port of the device.
  • The SNMP Version as configured on the device.
  • The Community as configured on the device.
  • Select Custom OID and enter the OID you want to monitor. In this example, we use 1.3.6.1.4.1.6574.4.3.2.1.0 that corresponds to the UPS Battery Voltage value of a UPS device.
• Click Start to execute the request.

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The value 29,14885454 is correct and includes a comma but it is read as a string value and not a float value.

• In SNMP Tester, set Read As to Float.
• Click Start to execute the new request.

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The value 2914885454 is incorrect because it does not contain a decimal separator. The float value returned by the SNMP request must contain a dot '.' as decimal separator, otherwise PRTG cannot interpret the value.

Solution: Create an SNMP Custom String Sensor

The SNMP Custom String sensor allows you to extract a floating point value from a string result using a regular expression.

• Add an SNMP Custom String sensor to the device.
• Under OID Value, enter the OID. In our example it is 1.3.6.1.4.1.6574.4.3.2.1.0.
• In section Extended Processing, select Extract a numeric value using a regular expression.
  • Under Regular Expression, enter ([0-9]+),([0-9]+) to convert the float value into an integer value.
  • Under Index of Capturing Group, enter 2.
  • Under Decimal Separator, enter a comma ','.
  • Under Thousands Separator, enter a comma ','.
• Save your settings.

The sensor now shows the correct value.
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See Also

• PRTG Manual: Regular Expressions